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 | 1 |
| 3 | 3 |
| 4 | 7 |
| 5 | 36 |
| 6 | 139 |
| 7 | 1036 |
| 8 | 5711 |
| 9 | 56355 |
| 10 | 408354 |
| 11 | 5045370 |
| 12 | 45605881 |
| 13 | 679409158 |
| 14 | 7390305396 |
| 15 | 129195427716 |
| 16 | 1647470410551 |
| 17 | 33114233390505 |
| 18 | 485292763088275 |
| 19 | 11038606786054201 |
| 20 | 183049273155939442 |
| 21 | 4652371578279864792 |