n | a(n) |
---|---|
0 | 0 |
1 | 1 |
2 | 4 |
3 | 15 |
4 | 64 |
5 | 325 |
6 | 1956 |
7 | 13699 |
8 | 109600 |
9 | 986409 |
10 | 9864100 |
11 | 108505111 |
12 | 1302061344 |
13 | 16926797485 |
14 | 236975164804 |
15 | 3554627472075 |
16 | 56874039553216 |
17 | 966858672404689 |
18 | 17403456103284420 |
19 | 330665665962403999 |
20 | 6613313319248080000 |
21 | 138879579704209680021 |
22 | 3055350753492612960484 |
[0,1,4,15,64,325,1956,13699,109600,986409,9864100, 108505111,1302061344,16926797485,236975164804, 3554627472075,56874039553216,966858672404689, 17403456103284420,330665665962403999, 6613313319248080000,138879579704209680021, 3055350753492612960484] |