n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | -2 |
3 | -6 |
4 | 24 |
5 | 120 |
6 | -720 |
7 | -5040 |
8 | 40320 |
9 | 362880 |
10 | -3628800 |
11 | -39916800 |
12 | 479001600 |
13 | 6227020800 |
14 | -87178291200 |
15 | -1307674368000 |
16 | 20922789888000 |
17 | 355687428096000 |
18 | -6402373705728000 |
19 | -121645100408832000 |
20 | 2432902008176640000 |
[1,1,-2,-6,24,120,-720,-5040,40320,362880, -3628800,-39916800,479001600,6227020800, -87178291200,-1307674368000,20922789888000, 355687428096000,-6402373705728000, -121645100408832000,2432902008176640000] |