P26 [Number Theory] - Turkish NMO 1st Round - 2002
Source:
August 10, 2014
modular arithmetic
Problem Statement
Which of the following is the set of all perfect squares that can be written as sum of three odd composite numbers?a)\ \{(2k + 1)^2 : k \geq 0\}
b)\ \{(4k + 3)^2 : k \geq 1\}
c)\ \{(2k + 1)^2 : k \geq 3\}
d)\ \{(4k + 1)^2 : k \geq 2\}