This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 6 | 1 |
| 7 | 14 |
| 8 | 120 |
| 9 | 816 |
| 10 | 4845 |
| 11 | 26334 |
| 12 | 134596 |
| 13 | 657800 |
| 14 | 3108105 |
| 15 | 14307150 |
| 16 | 64512240 |
| 17 | 286097760 |
| 18 | 1251677700 |
| 19 | 5414950296 |
| 20 | 23206929840 |
| 21 | 98672427616 |
| 22 | 416714805914 |
| 23 | 1749695026860 |
| 24 | 7309837001104 |
| 25 | 30405943383200 |
| 26 | 125994627894135 |
| 27 | 520341450264090 |
| 28 | 2142582442263900 |
| 29 | 8799226775309880 |