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 | 16 |
| 5 | 20 |
| 6 | 168 |
| 7 | 168 |
| 8 | 912 |
| 9 | 972 |
| 10 | 4620 |
| 11 | 4840 |
| 12 | 21064 |
| 13 | 22360 |
| 14 | 93912 |
| 15 | 99080 |
| 16 | 406416 |
| 17 | 428876 |
| 18 | 1739220 |
| 19 | 1828104 |
| 20 | 7364236 |
| 21 | 7716408 |
| 22 | 30987704 |
| 23 | 32355664 |
| 24 | 129676104 |
| 25 | 135002920 |
| 26 | 540592520 |
| 27 | 561188088 |
| 28 | 2245972472 |
| 29 | 2325812528 |