|
13 (number)
13 (thirteen) is the natural number following 12 (number), 12 and preceding 14 (number), 14. Folklore surrounding the number 13 appears in many cultures around the world: one theory is that this is due to the cultures employing lunar-solar calendars (there are approximately 12.41 lunations per solar year, and hence 12 "true months" plus a smaller, and often portentous, thirteenth month). This can be witnessed, for example, in the "Twelve Days of Christmas" of Western European tradition. In mathematics The number 13 is a prime number, happy number and a lucky number. It is a twin prime with 11 (number), 11, as well as a cousin prime with 17 (number), 17. It is the second of only 3 Wilson prime, Wilson primes: 5, 13, and 563 (number), 563. A 13-sided regular polygon is called a tridecagon. List of basic calculations In languages Grammar * In all Germanic languages, 13 is the first Compound (linguistics), compound number; the numbers 11 and 12 have their own names. * The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Base 13
There are many different numeral systems, that is, writing systems for expressing numbers. By culture / time period "A ''base'' is a natural number B whose ''powers'' (B multiplied by itself some number of times) are specially designated within a numerical system." The term is not equivalent to radix, as it applies to all numerical notation systems (not just positional ones with a radix) and most systems of spoken numbers. Some systems have two bases, a smaller (subbase) and a larger (base); an example is Roman numerals, which are organized by fives (V=5, L=50, D=500, the subbase) and tens (X=10, C=100, M=1,000, the base). By type of notation Numeral systems are classified here as to whether they use positional notation (also known as place-value notation), and further categorized by radix or base. Standard positional numeral systems The common names are derived Hexadecimal#Etymology, somewhat arbitrarily from a mix of Latin and Greek language, Greek, in some cases incl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tridecagon
In geometry, a tridecagon or triskaidecagon or 13-gon is a thirteen-sided polygon. Regular tridecagon A ''regular polygon, regular tridecagon'' is represented by Schläfli symbol . The measure of each internal angle of a Regular polygon, regular tridecagon is approximately 152.308 degree (angle), degrees, and the area with side length ''a'' is given by :A = \fraca^2 \cot \frac \simeq 13.1858\,a^2. Construction As 13 is a Pierpont prime but not a Fermat prime, the regular tridecagon cannot be constructible polygon, constructed using a compass and straightedge. However, it is constructible using neusis construction, neusis, or an angle trisector. The following is an animation from a ''neusis construction'' of a regular tridecagon with radius of circumcircle \overline = 12, according to Andrew M. Gleason, based on the angle trisection by means of the Tomahawk (geometry), Tomahawk (light blue). An approximate construction of a regular tridecagon using straightedge and compass (d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
169 (number)
169 (one hundred ndsixty-nine) is the natural number following 168 and preceding 170. In mathematics 169 is an odd number, a composite number, and a deficient number. 169 is a square number: 13 × 13 = 169, and if each number is reversed the equation is still true: 31 × 31 = 961. 144 shares this property: 12 × 12 = 144, 21 × 21 = 441. 169 is one of the few squares to also be a centered hexagonal number. Like all odd squares, it is a centered octagonal number. 169 is an odd-indexed Pell number, thus it is also a Markov number, appearing in the solutions (2, 169, 985), (2, 29, 169), (29, 169, 14701), etc. 169 is the sum of seven consecutive primes: 13 + 17 + 19 + 23 + 29 + 31 + 37. 169 is a difference in consecutive cubes, equaling 8^3-7^3. In other fields * 169 is known in the computing world as the first number of an automatic IPv4 address assigned by TCP/IP The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the commun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
156 (number)
156 (one hundred ndfifty-six) is the natural number, following 155 and preceding 157. In mathematics 156 is an abundant number, a pronic number, a dodecagonal number, and a refactorable number. 156 is the number of graphs on 6 unlabeled nodes. 156 is a repdigit in base 5 (1111), and also in bases 25, 38, 51, 77, and 155. 156 degrees is the internal angle of a pentadecagon In geometry, a pentadecagon or pentakaidecagon or 15-gon is a fifteen-sided polygon. Regular pentadecagon A '' regular pentadecagon'' is represented by Schläfli symbol . A regular pentadecagon has interior angles of 156 °, and with a side .... References External links The Number 156 156th Street (3rd Avenue El) {{DEFAULTSORT:156 (Number) Integers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
143 (number)
143 (one hundred ndforty-three) is the natural number following 142 and preceding 144. It is one less than a gross. In media * On '' Mister Rogers' Neighborhood'': "Transformations", 143 is used to mean "I love you". 1 meaning I for 1 letter, 4 meaning Love for the 4 letters, and 3 meaning You for the 3 letters. Reportedly, Fred Rogers maintained his weight at exactly for the last thirty years of his life, and associated the number with the phrase "I love you". * Jake Shimabukuro released the song "143" based on his experience in high school when 143 was sent on a pager to indicate "I Love You". * Sal Governale of '' The Howard Stern Show'' had a long running saga on the show about his wife who had an emotional friend. He discovered the severity of their relationship when he read their text messages and emails which included "143", shorthand for "I love you". * " Case 143", song by Stray Kids. In popular culture *143. A popular pager number to communicate "I love you" (b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
130 (number)
130 (one hundred ndthirty) is the natural number following 129 and preceding 131. In mathematics 130 is a sphenic number. It is a noncototient In number theory, a noncototient is a positive integer that cannot be expressed as the difference between a positive integer and the number of coprime integers below it. That is, , where stands for Euler's totient function In number theory ... since there is no answer to the equation ''x'' - φ(''x'') = 130. 130 is the only integer that is the sum of the squares of its first four divisors, including 1: 12 + 22 + 52 + 102 = 130. 130 is the largest number that cannot be written as the sum of four hexagonal numbers. 130 equals both 27 + 2 and 53 + 5 and is therefore a ''doubly strictly '' number. In other fields * A 130-30 fund or a ratio up to 150/50 is a type of collective investment vehicle References {{DEFAULTSORT:130 (Number) Integers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
117 (number)
117 (one hundred [and] seventeen) is the natural number following 116 (number), 116 and preceding 118 (number), 118. In mathematics 117 is the smallest possible length of the longest edge of an integer Heronian tetrahedron (a tetrahedron whose edge lengths, face areas and volume are all integers). Its other edge lengths are 51, 52, 53, 80 and 84. 117 is a pentagonal number. In other fields 117 can be a substitute for the number 17 (number), 17, which is Heptadecaphobia, considered unlucky in Italy. When Renault exported the Renault 15 and 17, R17 to Italy, it was renamed R117. In the Danish language the number 117 () is often used as a Hyperbole, hyperbolic term to represent an arbitrary but large number. See also * 117 (other) References Integers {{Num-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
104 (number)
104 (one hundred ndfour) is the natural number following 103 and preceding 105. In mathematics 104 is a refactorable number and a primitive semiperfect number. The smallest known 4-regular matchstick graph has 104 edges and 52 vertices, where four unit line segments intersect at every vertex. The second largest sporadic group \mathbb has a McKay–Thompson series, representative of a principal modular function is T_(\tau), with constant term a(0) = 104: :j_(\tau) = T_(\tau)+104 = \frac + 104 + 4372q + 96256q^2 + \cdots The Tits group \mathbb , which is the only finite simple group to classify as either a ''non-strict'' group of Lie type or sporadic group, holds a minimal faithful complex representation in 104 dimensions. References * Wells, D. ''The Penguin Dictionary of Curious and Interesting Numbers ''The Penguin Dictionary of Curious and Interesting Numbers'' is a reference book for recreational mathematics and elementary number theory written by David ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
91 (number)
91 (ninety-one) is the natural number following 90 (number), 90 and preceding 92 (number), 92. In mathematics 91 is: * the twenty-seventh distinct semiprime and the second of the form (7.q), where q is a higher prime. * the aliquot sum of 91 is 21; itself a semiprime, within an aliquot sequence of two composite numbers (91, 21, 11, 1, 0) to the prime in the 11-aliquot tree. 91 is the fourth composite number in the 11-aliquot tree. (91, 51, 21, 18). * the 13th triangular number. * a hexagonal number, one of the few such numbers to also be a centered hexagonal number. * a centered nonagonal number. * a centered cube number. * a square pyramidal number, being the sum of the squares of the first six integers. * the smallest positive integer expressible as a sum of two cubes in two different ways if negative roots are allowed (alternatively the sum of two cubes and the difference of two cubes): . (See 1729 (number), 1729 for more details). This implies that 91 is the second cabtaxi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
78 (number)
78 (seventy-eight) is the natural number following 77 (number), 77 and preceding 79 (number), 79. In mathematics 78 is: *the 5th discrete tri-prime; or also termed Sphenic number, and the 4th of the form (2.3.r). *an abundant number with an aliquot sum of 90 (number), 90; within an aliquot sequence of nine composite numbers (78, 90 (number), 90,144 (number), 144,259 (number), 259,45 (number), 45,33 (number), 33,15 (number), 15,9 (number), 9,4 (number), 4,3 (number), 3,1 (number), 1,0) to the Prime in the 3 (number), 3-aliquot tree. *a semiperfect number, as a multiple of a perfect number. *the 12th triangular number. *a palindromic number in bases 5 (3035), 7 (1417), 12 (6612), 25 (3325), and 38 (2238). *a Harshad number in bases 3, 4, 5, 6, 7, 13 and 14. *an Erdős–Woods number, since it is possible to find sequences of 78 consecutive integers such that each inner member shares a factor with either the first or the last member. *the dimension of the Simple Lie group#Exception ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
65 (number)
65 (sixty-five) is the natural number following 64 and preceding 66. In mathematics 65 is the nineteenth distinct semiprime, (5.13); and the third of the form (5.q), where q is a higher prime. 65 has a prime aliquot sum of 19 within an aliquot sequence of one composite numbers (65, 19, 1,0) to the prime; as the first member' of the 19-aliquot tree. It is an octagonal number. It is also a Cullen number. Given 65, the Mertens function returns 0. This number is the magic constant of a 5x5 normal magic square: \begin 17 & 24 & 1 & 8 & 15 \\ 23 & 5 & 7 & 14 & 16 \\ 4 & 6 & 13 & 20 & 22 \\ 10 & 12 & 19 & 21 & 3 \\ 11 & 18 & 25 & 2 & 9 \end. This number is also the magic constant of n-Queens Problem for n = 5. 65 is the smallest integer that can be expressed as a sum of two distinct positive squares in two (or more) ways, 65 = 82 + 12 = 72 + 42. It appears in the Padovan sequence, preceded by the terms 28, 37, 49 (it is the sum of the first two of these). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
52 (number)
52 (fifty-two) is the natural number following 51 (number), 51 and preceding 53 (number), 53. In mathematics Fifty-two is * a composite number; a square-prime, of the form where is some prime larger than It is the sixth of this form and the fifth of the form * the 5th Bell number, the number of ways to partition a set of 5 objects. * a decagonal number. * with an aliquot sum of 46 (number), 46; within an aliquot sequence of seven composite numbers to the prime in the 3 (number), 3-aliquot tree. This sequence does not extend above 52 because it is, * an untouchable number, since it is never the sum of proper divisors of any number. It is the first untouchable number larger than 2 and 5. * a noncototient since it is not equal to for any * a vertically symmetrical number. In other fields Fifty-two is: * The number of cards in a standard deck of playing cards, not counting joker (playing card), Jokers or advertisement cards References {{Integers, zero In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
