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 | 5 |
| 3 | 84 |
| 4 | 4004 |
| 5 | 494760 |
| 6 | 150120600 |
| 7 | 107969547840 |
| 8 | 179605731622464 |
| 9 | 678695382464158080 |
| 10 | 5745964983105758544000 |
| 11 | 107798142804281290451059200 |
| 12 | 4441362930723337358985334172160 |
| 13 | 398854836980938754158182857661404160 |
| 14 | 77576833096847783279235708819073596288000 |