E

(1+1/N)n
2.71
2.71828182845 ふなびと、やつはいっぱつはしご


N!
0
1
1x1
2x1
3x2x1
4x3x2x1
5x4x3x2x1
6x5x4x3x2x1
7x6x5x4x3x2x1
8x7x6x5x4x3x2x1
9x8x7x6x5x4x3x2x1