a^4 + 4a^3 + 11a^2 + 6a+ 2 a sum of 3 squares and divisible by 4 for odd a
Source: Spanish Mathematical Olympiad 1981 P8
December 23, 2022
number theorySum of Squaresdivisible
Problem Statement
If is an odd number, show that is a sum of three squares and is divisible by .