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 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 13 |
| 4 | 44 |
| 5 | 181 |
| 6 | 662 |
| 7 | 2521 |
| 8 | 9368 |
| 9 | 35113 |
| 10 | 130922 |
| 11 | 489061 |
| 12 | 1824836 |
| 13 | 6811741 |
| 14 | 25420670 |
| 15 | 94875313 |
| 16 | 354076208 |
| 17 | 1321442641 |
| 18 | 4931681234 |
| 19 | 18405321661 |
| 20 | 68689566044 |
| 21 | 256353060613 |
| 22 | 956722558310 |
| 23 | 3570537526921 |
| 24 | 13325427195080 |
| 25 | 49731172316281 |
| 26 | 185599261007162 |