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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 24 |
| 5 | 60 |
| 6 | 240 |
| 7 | 1260 |
| 8 | 28224 |
| 9 | 241920 |
| 10 | 2181600 |
| 11 | 21621600 |
| 12 | 315342720 |
| 13 | 4358914560 |
| 14 | 61607407680 |
| 15 | 912518006400 |
| 16 | 15142006978560 |
| 17 | 265601118182400 |
| 18 | 4877947688140800 |
| 19 | 93691850626483200 |
| 20 | 1901787789077452800 |
| 21 | 40548028309147699200 |
| 22 | 904101131200045363200 |