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 | 6 |
| 3 | 0 |
| 4 | 74 |
| 5 | 0 |
| 6 | 1140 |
| 7 | 0 |
| 8 | 19562 |
| 9 | 0 |
| 10 | 357756 |
| 11 | 0 |
| 12 | 6824684 |
| 13 | 0 |
| 14 | 134166696 |
| 15 | 0 |
| 16 | 2697855082 |
| 17 | 0 |
| 18 | 55213424556 |
| 19 | 0 |
| 20 | 1146078241284 |
| 21 | 0 |
| 22 | 24067465856088 |
| 23 | 0 |
| 24 | 510351502965548 |
| 25 | 0 |
| 26 | 10911807871502232 |
| 27 | 0 |
| 28 | 234970037988773560 |
| 29 | 0 |
| 30 | 5091149074269149520 |
| 31 | 0 |
| 32 | 110912377099411850090 |
| 33 | 0 |