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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 6 |
| 6 | 35 |
| 7 | 260 |
| 8 | 2934 |
| 9 | 53768 |
| 10 | 1707627 |
| 11 | 96648020 |
| 12 | 9886429142 |
| 13 | 1842161884708 |
| 14 | 629505254017556 |
| 15 | 397043155634566696 |
| 16 | 464930596621838689900 |
| 17 | 1016021072554513545893264 |
| 18 | 4162479064042009639168386134 |
| 19 | 32096876145378032622994745784856 |