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 | 1 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | 0 |
| 8 | 0 |
| 9 | 0 |
| 10 | 0 |
| 11 | 0 |
| 12 | 1 |
| 13 | 64 |
| 14 | 4352 |
| 15 | 103680 |
| 16 | 2644488 |
| 17 | 48052224 |
| 18 | 922764744 |
| 19 | 15466088448 |
| 20 | 271484691944 |
| 21 | 4512300607488 |
| 22 | 78169637107873 |
| 23 | 1332149989277696 |
| 24 | 23596090882390538 |