n | a(n) |
---|---|
0 | 0 |
1 | 2 |
2 | -1 |
3 | 2 |
4 | -6 |
5 | 24 |
6 | -120 |
7 | 720 |
8 | -5040 |
9 | 40320 |
10 | -362880 |
11 | 3628800 |
12 | -39916800 |
13 | 479001600 |
14 | -6227020800 |
15 | 87178291200 |
16 | -1307674368000 |
17 | 20922789888000 |
18 | -355687428096000 |
19 | 6402373705728000 |
20 | -121645100408832000 |
21 | 2432902008176640000 |
22 | -51090942171709440000 |
[0,2,-1,2,-6,24,-120,720,-5040,40320,-362880, 3628800,-39916800,479001600,-6227020800, 87178291200,-1307674368000,20922789888000, -355687428096000,6402373705728000, -121645100408832000,2432902008176640000, -51090942171709440000] |