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 | 2 |
| 2 | 9 |
| 3 | 43 |
| 4 | 206 |
| 5 | 999 |
| 6 | 4915 |
| 7 | 24372 |
| 8 | 121698 |
| 9 | 611244 |
| 10 | 3085612 |
| 11 | 15645347 |
| 12 | 79639602 |
| 13 | 406809249 |
| 14 | 2084567381 |
| 15 | 10712007629 |
| 16 | 55187254157 |
| 17 | 284981396231 |
| 18 | 1474729519719 |
| 19 | 7646180479889 |
| 20 | 39713643612380 |
| 21 | 206600871071930 |
| 22 | 1076372569004514 |
| 23 | 5615363541987786 |
| 24 | 29331204404385053 |