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) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 3 |
| 5 | 6 |
| 6 | 24 |
| 7 | 148 |
| 8 | 1646 |
| 9 | 34040 |
| 10 | 1358852 |
| 11 | 106321628 |
| 12 | 16006173014 |
| 13 | 4525920859198 |
| 14 | 2404130854745735 |
| 15 | 2426376196165902704 |
| 16 | 4648429222263945620900 |
| 17 | 16788801124652327714275292 |
| 18 | 114722035311851620271616102401 |