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 | 2 |
| 3 | 7 |
| 4 | 31 |
| 5 | 156 |
| 6 | 936 |
| 7 | 6557 |
| 8 | 52457 |
| 9 | 472118 |
| 10 | 4721185 |
| 11 | 51933039 |
| 12 | 623196471 |
| 13 | 8101554127 |
| 14 | 113421757790 |
| 15 | 1701326366855 |
| 16 | 27221221869682 |
| 17 | 462760771784596 |
| 18 | 8329693892122733 |
| 19 | 158264183950331941 |
| 20 | 3165283679006638838 |