The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 20 |
| 3 | 36 |
| 4 | 440 |
| 5 | 1008 |
| 6 | 2052 |
| 7 | 20240 |
| 8 | 86688 |
| 9 | 116928 |
| 10 | 192024 |
| 11 | 354240 |
| 12 | 1460160 |
| 13 | 1902560 |
| 14 | 42451200 |
| 15 | 43007328 |
| 16 | 77299200 |
| 17 | 1595255040 |
| 18 | 4556027520 |
| 19 | 17973550080 |
| 20 | 34221035520 |
| 21 | 62863257600 |
| 22 | 76146739200 |
| 23 | 91506844800 |
| 24 | 602152462080 |
| 25 | 1106232422400 |
[2,20,36,440,1008,2052,20240,86688,116928,192024, 354240,1460160,1902560,42451200,43007328,77299200, 1595255040,4556027520,17973550080,34221035520, 62863257600,76146739200,91506844800,602152462080, 1106232422400] |