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 | 5 |
| 2 | 30 |
| 3 | 180 |
| 4 | 1080 |
| 5 | 6480 |
| 6 | 38880 |
| 7 | 233280 |
| 8 | 1399680 |
| 9 | 8398080 |
| 10 | 50388480 |
| 11 | 302330880 |
| 12 | 1813985280 |
| 13 | 10883911680 |
| 14 | 65303470080 |
| 15 | 391820820480 |
| 16 | 2350924922880 |
| 17 | 14105549537280 |
| 18 | 84633297223680 |
| 19 | 507799783342080 |