205 (two hundred
ndfive) is the
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 ...
following
204 and preceding
206
Year 206 ( CCVI) was a common year starting on Wednesday of the Julian calendar. At the time, it was known as the Year of the Consulship of Umbrius and Gavius (or, less frequently, year 959 ''Ab urbe condita''). The denomination 206 for this y ...
.
In mathematics
205 is a
lucky number
In number theory, a lucky number is a natural number in a set which is generated by a certain " sieve". This sieve is similar to the sieve of Eratosthenes that generates the primes, but it eliminates numbers based on their position in the rema ...
, and a
Wolstenholme number.
On an infinite chessboard, a
knight
A knight is a person granted an honorary title of a knighthood by a head of state (including the pope) or representative for service to the monarch, the church, or the country, especially in a military capacity.
The concept of a knighthood ...
can reach exactly 205 squares within four moves or less. There are 205 different ways of forming a
connected graph by adding six edges to a set of five labeled vertices.
References
Integers
{{Num-stub