20/08/29 10:57:14.18 nEvr3uHf.net
5^{n-1} ≡ 1^(n-1) = 1 (mod 4)
5^{n-1} = 4m + 1,
5^n + 1 = 20m + 6 = 2(10m+3),
20/08/29 10:57:14.18 nEvr3uHf.net
5^{n-1} ≡ 1^(n-1) = 1 (mod 4)
5^{n-1} = 4m + 1,
5^n + 1 = 20m + 6 = 2(10m+3),
20/08/29 10:57:14.18 nEvr3uHf.net
5^{n-1} ≡ 1^(n-1) = 1 (mod 4)
5^{n-1} = 4m + 1,
5^n + 1 = 20m + 6 = 2(10m+3),