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 | 1 |
| 4 | 7 |
| 5 | 50 |
| 6 | 371 |
| 7 | 3023 |
| 8 | 26962 |
| 9 | 263503 |
| 10 | 2806759 |
| 11 | 32439638 |
| 12 | 404794391 |
| 13 | 5429249279 |
| 14 | 77941628854 |
| 15 | 1193095348531 |
| 16 | 19406686847167 |
| 17 | 334372746780002 |
| 18 | 6085085617645595 |
| 19 | 116659595136911903 |
| 20 | 2350442395504338154 |
| 21 | 49658877772798776295 |
| 22 | 1097945956312067172727 |