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 | 120 |
| 7 | 210 |
| 8 | 40656 |
| 9 | 363384 |
| 10 | 2117520 |
| 11 | 9980190 |
| 12 | 520250280 |
| 13 | 9496208436 |
| 14 | 109522054824 |
| 15 | 982593614730 |
| 16 | 28426015541280 |
| 17 | 762523155318000 |
| 18 | 14192088961120416 |
| 19 | 204618562767970614 |
| 20 | 4906638448867994040 |
| 21 | 154037798077765359660 |
| 22 | 4000484484370905087480 |