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 | 2 |
| 3 | 6 |
| 4 | 23 |
| 5 | 116 |
| 6 | 702 |
| 7 | 4945 |
| 8 | 39726 |
| 9 | 358596 |
| 10 | 3593759 |
| 11 | 39596032 |
| 12 | 475750740 |
| 13 | 6190873441 |
| 14 | 86740653730 |
| 15 | 1301942638170 |
| 16 | 20842037779079 |
| 17 | 354469561697988 |
| 18 | 6382795892548194 |
| 19 | 121310901632237857 |
| 20 | 2426864464216669694 |
| 21 | 50975856191753357928 |
| 22 | 1121692313538562441535 |