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 | 12 |
| 5 | 68 |
| 6 | 473 |
| 7 | 3998 |
| 8 | 39327 |
| 9 | 443599 |
| 10 | 5629807 |
| 11 | 79486044 |
| 12 | 1235018598 |
| 13 | 20946691457 |
| 14 | 385025599130 |
| 15 | 7624623236381 |
| 16 | 161823815625933 |
| 17 | 3664505951884255 |
| 18 | 88189911547566082 |
| 19 | 2247691180645108608 |
| 20 | 60480432646998315279 |
| 21 | 1713328345952593367876 |
| 22 | 50970518521542636421145 |