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 | 8 |
| 2 | 20 |
| 3 | 1 |
| 4 | 1680 |
| 5 | 1 |
| 6 | 90720 |
| 7 | 1 |
| 8 | 4435200 |
| 9 | 1 |
| 10 | 207567360 |
| 11 | 1 |
| 12 | 6538371840000 |
| 13 | 1 |
| 14 | 423437414400 |
| 15 | 1 |
| 16 | 67580611338240000 |
| 17 | 1 |
| 18 | 35763659520196608000 |
| 19 | 1 |
| 20 | 6155242080686899200000 |
| 21 | 1 |
| 22 | 117509166994931712000000 |
| 23 | 1 |
| 24 | 15244417230585693025075200000 |
| 25 | 1 |
| 26 | 1799300365026394374144000000 |