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 | 4 |
| 2 | 39 |
| 3 | 392 |
| 4 | 4420 |
| 5 | 52272 |
| 6 | 644231 |
| 7 | 8179600 |
| 8 | 106376580 |
| 9 | 1410528080 |
| 10 | 19006875580 |
| 11 | 259613952864 |
| 12 | 3587352778256 |
| 13 | 50068405195200 |
| 14 | 704925148185495 |
| 15 | 10001318622631200 |
| 16 | 142866058397606500 |
| 17 | 2053248549639210000 |