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 | 0 |
| 2 | 1 |
| 3 | 4 |
| 4 | 14 |
| 5 | 66 |
| 6 | 397 |
| 7 | 2626 |
| 8 | 18797 |
| 9 | 148238 |
| 10 | 1281134 |
| 11 | 11943790 |
| 12 | 118998365 |
| 13 | 1262189748 |
| 14 | 14203022537 |
| 15 | 168835162632 |
| 16 | 2111832477426 |
| 17 | 27708387132906 |
| 18 | 380355066174121 |
| 19 | 5449577398256414 |
| 20 | 81316095965242989 |
| 21 | 1261149374033472626 |
| 22 | 20293627142875917978 |
| 23 | 338263983223664609198 |