n | a(n) |
---|---|
0 | 0 |
1 | 0 |
2 | 0 |
3 | 0 |
4 | 18 |
5 | 90 |
6 | 690 |
7 | 4830 |
8 | 40110 |
9 | 362670 |
10 | 3628590 |
11 | 39914490 |
12 | 478999290 |
13 | 6226990770 |
14 | 87178261170 |
15 | 1307674337970 |
16 | 20922789857970 |
17 | 355687427585490 |
18 | 6402373705217490 |
19 | 121645100399132310 |
20 | 2432902008166940310 |
[0,0,0,0,18,90,690,4830,40110,362670,3628590, 39914490,478999290,6226990770,87178261170, 1307674337970,20922789857970,355687427585490, 6402373705217490,121645100399132310, 2432902008166940310] |