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) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 8 |
| 3 | 98 |
| 4 | 1440 |
| 5 | 23389 |
| 6 | 404712 |
| 7 | 7314724 |
| 8 | 136476912 |
| 9 | 2608808180 |
| 10 | 50828498336 |
| 11 | 1005682252458 |
| 12 | 20152470321984 |
| 13 | 408149824237302 |
| 14 | 8341496306085040 |
| 15 | 171812412714350280 |
| 16 | 3562961488550366480 |
| 17 | 74328284438252301996 |
| 18 | 1558783863783469298016 |
| 19 | 32844108784368485209320 |
| 20 | 694957689921176181019520 |