C= {m divide m ∈ Ν si 1^2+2^2+3^2+4^2...m^2}

Răspuns :

C={1, 5, 14, 30, 55, 91, 140, 204, 285, 385......}
1²=1
2²=4
3²=9
4²=16
5²=25
6²=36
7²=49
8²=64
9²=81
10²=100
........