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 | 8 |
| 5 | 10 |
| 6 | 24 |
| 7 | 84 |
| 8 | 192 |
| 9 | 432 |
| 10 | 2880 |
| 11 | 15840 |
| 12 | 34560 |
| 13 | 224640 |
| 14 | 483840 |
| 15 | 3628800 |
| 16 | 116121600 |
| 17 | 493516800 |
| 18 | 1045094400 |
| 19 | 9928396800 |
| 20 | 20901888000 |
| 21 | 219469824000 |
| 22 | 9656672256000 |
| 23 | 111051730944000 |
| 24 | 231760134144000 |
| 25 | 2897001676800000 |
| 26 | 30128817438720000 |
| 27 | 406739035422720000 |