21/02/08 23:45:43.26 ImzyO0ab.net
100個で体感
> n=1:100
> (n*(n+1))%%10
[1] 2 6 2 0 0 2 6 2 0 0 2 6 2 0 0 2 6 2 0 0 2 6 2 0 0 2 6 2 0 0 2 6 2 0 0 2 6
[38] 2 0 0 2 6 2 0 0 2 6 2 0 0 2 6 2 0 0 2 6 2 0 0 2 6 2 0 0 2 6 2 0 0 2 6 2 0
[75] 0 2 6 2 0 0 2 6 2 0 0 2 6 2 0 0 2 6 2 0 0 2 6 2 0 0
>