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) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 8 |
| 4 | 28 |
| 5 | 96 |
| 6 | 420 |
| 7 | 1824 |
| 8 | 9696 |
| 9 | 51360 |
| 10 | 322560 |
| 11 | 2021760 |
| 12 | 14670720 |
| 13 | 106323840 |
| 14 | 875992320 |
| 15 | 7211151360 |
| 16 | 66526064640 |
| 17 | 613365903360 |
| 18 | 6265340928000 |
| 19 | 63970228224000 |
| 20 | 716840699904000 |
| 21 | 8030097782784000 |
| 22 | 97954524315648000 |