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 | 56 |
| 4 | 606 |
| 5 | 0 |
| 6 | 0 |
| 7 | 27456 |
| 8 | 123156 |
| 9 | 0 |
| 10 | 0 |
| 11 | 3745512 |
| 12 | 9217112 |
| 13 | 0 |
| 14 | 0 |
| 15 | 95209152 |
| 16 | 188066718 |
| 17 | 0 |
| 18 | 0 |
| 19 | 1144371624 |
| 20 | 1960489800 |
| 21 | 0 |
| 22 | 0 |
| 23 | 8505838656 |
| 24 | 13289979912 |
| 25 | 0 |
| 26 | 0 |
| 27 | 45755357024 |
| 28 | 67080028224 |
| 29 | 0 |
| 30 | 0 |
| 31 | 195411318912 |
| 32 | 272570040468 |
| 33 | 0 |
| 34 | 0 |