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) |
|---|---|
| 3 | 9 |
| 4 | 29 |
| 5 | 99 |
| 6 | 354 |
| 7 | 1290 |
| 8 | 4762 |
| 9 | 17663 |
| 10 | 65733 |
| 11 | 244923 |
| 12 | 913383 |
| 13 | 3407329 |
| 14 | 12713796 |
| 15 | 47443092 |
| 16 | 177050612 |
| 17 | 660741597 |
| 18 | 2465886087 |
| 19 | 9202736493 |
| 20 | 34344949105 |
| 21 | 128176812671 |
| 22 | 478361888166 |
| 23 | 1785269817246 |
| 24 | 6662715837966 |
| 25 | 24865590090907 |
| 26 | 92799638767689 |
| 27 | 346332952127775 |