n | a(n) |
---|---|
0 | 0 |
1 | 1 |
2 | 4 |
3 | 21 |
4 | 144 |
5 | 1245 |
6 | 13140 |
7 | 164745 |
8 | 2399040 |
9 | 39834585 |
10 | 742940100 |
11 | 15374360925 |
12 | 349484058000 |
13 | 8654336615925 |
14 | 231842662751700 |
15 | 6679510641428625 |
16 | 205916703920928000 |
17 | 6762863294018456625 |
18 | 235719416966063530500 |
19 | 8689887736412502745125 |
[0,1,4,21,144,1245,13140,164745,2399040,39834585, 742940100,15374360925,349484058000,8654336615925, 231842662751700,6679510641428625, 205916703920928000,6762863294018456625, 235719416966063530500,8689887736412502745125] |