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 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 16 |
| 4 | 65 |
| 5 | 576 |
| 6 | 2275 |
| 7 | 27840 |
| 8 | 78489 |
| 9 | 236800 |
| 10 | 767151 |
| 11 | 13264560 |
| 12 | 31184725 |
| 13 | 640564848 |
| 14 | 2082421125 |
| 15 | 5514535936 |
| 16 | 10924376001 |
| 17 | 279876280320 |
| 18 | 584912713825 |
| 19 | 16888996800000 |
| 20 | 37538691697521 |
| 21 | 91766133606400 |
| 22 | 272224952406045 |
| 23 | 9248286151802880 |
| 24 | 17279191734765625 |