21/03/03 18:13:46.30 SY070HAY.net
>>446
N^3 + 6 = (N^3 - 1) + 7
= (N-1)(N^2 + N + 1) + 7
= (N-1){(N-4)(N-9) + 7(2N-5)} + 7
= (N-1)(N-4)(N-9) + 7(N-2)(2N-3)
≡ (N-1)(N-4)(N-9) (mod 7)
が使えるかも
21/03/03 18:13:46.30 SY070HAY.net
>>446
N^3 + 6 = (N^3 - 1) + 7
= (N-1)(N^2 + N + 1) + 7
= (N-1){(N-4)(N-9) + 7(2N-5)} + 7
= (N-1)(N-4)(N-9) + 7(N-2)(2N-3)
≡ (N-1)(N-4)(N-9) (mod 7)
が使えるかも