Conjecture Every integer is a sum of four cubes of integers. Theorem(Dem`yanenko) Every integer such that n not = 4,5 mod 9 is a sum of four cubes of integers. Theme Every integer such that n = 4,5 mod 9 is a sum of four cubes of integers? So,I searched the solutions of n=a^3+b^3+c^3+d^3 under the condition n=4,5 mod 9,n<10000. Because there were many solutions, I adopted the smallest solutions. n=a^3+b^3+c^3+d^3