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 | 1 |
| 4 | 8 |
| 5 | 20 |
| 6 | 16 |
| 7 | 280 |
| 8 | 4480 |
| 9 | 64 |
| 10 | 44800 |
| 11 | 49280 |
| 12 | 1971200 |
| 13 | 1830400 |
| 14 | 14350336 |
| 15 | 896896000 |
| 16 | 74547200 |
| 17 | 243955712000 |
| 18 | 6823936000 |
| 19 | 109062553600 |
| 20 | 52973240320000 |
| 21 | 51913775513600 |
| 22 | 3359126650880000 |
| 23 | 93815608606720000 |
| 24 | 2101469632790528000 |