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 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 24 |
| 5 | 600 |
| 6 | 7560 |
| 7 | 61320 |
| 8 | 351120 |
| 9 | 1515024 |
| 10 | 5266800 |
| 11 | 15531120 |
| 12 | 40308840 |
| 13 | 94534440 |
| 14 | 204228024 |
| 15 | 412284600 |
| 16 | 786283680 |
| 17 | 1428742560 |
| 18 | 2490276960 |
| 19 | 4186173024 |
| 20 | 6816915000 |
| 21 | 10793253240 |
| 22 | 16666437480 |
| 23 | 25164280680 |
| 24 | 37233759024 |
| 25 | 54090894000 |
| 26 | 77278702800 |