n | a(n) |
---|---|
0 | 1 |
1 | 0 |
2 | 4 |
3 | 21 |
4 | 204 |
5 | 2500 |
6 | 38709 |
7 | 730420 |
8 | 16409180 |
9 | 430786429 |
10 | 13019414196 |
11 | 447437830704 |
12 | 17306961847705 |
13 | 746907935199264 |
14 | 35695643204860420 |
15 | 1876878693983656605 |
16 | 107956500727342113004 |
17 | 6758630146906528885412 |
18 | 458470139353155531447869 |
[1,0,4,21,204,2500,38709,730420,16409180, 430786429,13019414196,447437830704,17306961847705, 746907935199264,35695643204860420, 1876878693983656605,107956500727342113004, 6758630146906528885412,458470139353155531447869] |