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 | 12 |
| 2 | 240 |
| 3 | 4032 |
| 4 | 34560 |
| 5 | 101376 |
| 6 | 50319360 |
| 7 | 6635520 |
| 8 | 451215360 |
| 9 | 42361159680 |
| 10 | 1471492915200 |
| 11 | 1758147379200 |
| 12 | 417368899584000 |
| 13 | 15410543984640 |
| 14 | 141874849382400 |
| 15 | 28026642660065280 |
| 16 | 922166952040857600 |
| 17 | 19725496300339200 |
| 18 | 2163255728265599385600 |
| 19 | 36926129074234982400 |