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 | 2 |
| 3 | 3 |
| 4 | 12 |
| 5 | 20 |
| 6 | 60 |
| 7 | 84 |
| 8 | 672 |
| 9 | 1512 |
| 10 | 5040 |
| 11 | 7920 |
| 12 | 47520 |
| 13 | 56160 |
| 14 | 157248 |
| 15 | 393120 |
| 16 | 6289920 |
| 17 | 8225280 |
| 18 | 37013760 |
| 19 | 41368320 |
| 20 | 275788800 |
| 21 | 579156480 |
| 22 | 1820206080 |
| 23 | 2203407360 |
| 24 | 26440888320 |
| 25 | 73446912000 |
| 26 | 173601792000 |
| 27 | 585906048000 |
| 28 | 3281073868800 |
| 29 | 4137006182400 |
| 30 | 20685030912000 |