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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 3 |
| 6 | 16 |
| 7 | 78 |
| 8 | 397 |
| 9 | 2037 |
| 10 | 10820 |
| 11 | 58349 |
| 12 | 320824 |
| 13 | 1790189 |
| 14 | 10125858 |
| 15 | 57938771 |
| 16 | 334941363 |
| 17 | 1953830203 |
| 18 | 11489589280 |
| 19 | 68053757016 |
| 20 | 405714603234 |
| 21 | 2433001205088 |
| 22 | 14668531344984 |
| 23 | 88869454457853 |
| 24 | 540834122500464 |