natural number
In mathematics, the natural numbers are the numbers 0, 1, 2, 3, and so on, possibly excluding 0. Some start counting with 0, defining the natural numbers as the non-negative integers , while others start with 1, defining them as the positive in ...
261
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Year 261 (Roman numerals, CCLXI) was a common year starting on Tuesday of the Julian calendar. At the time, it was known as the Year of the Consulship of Gallienus and Taurus (or, less frequently, year 1014 ''Ab urbe condita''). The ...
.
In mathematics
260 is:
* an
abundant number
In number theory, an abundant number or excessive number is a positive integer for which the sum of its proper divisors is greater than the number. The integer 12 is the first abundant number. Its proper divisors are 1, 2, 3, 4 and 6 for a total ...
* an
Ulam number
In mathematics, the Ulam numbers comprise an integer sequence devised by and named after Stanislaw Ulam, who introduced it in 1964. The standard Ulam sequence (the (1, 2)-Ulam sequence) starts with ''U''1 = 1 and ''U''2 =&nbs ...
magic constant
The magic constant or magic sum of a magic square is the sum of numbers in any row, column, or diagonal of the magic square. For example, the magic square shown below has a magic constant of 15. For a normal magic square of order ''n'' – that is ...
of the normal
magic square
In mathematics, especially History of mathematics, historical and recreational mathematics, a square array of numbers, usually positive integers, is called a magic square if the sums of the numbers in each row, each column, and both main diago ...
of order 8
In other fields
Pre-Columbian
In the history of the Americas, the pre-Columbian era, also known as the pre-contact era, or as the pre-Cabraline era specifically in Brazil, spans from the initial peopling of the Americas in the Upper Paleolithic to the onset of European col ...