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 | 2 |
| 4 | 9 |
| 5 | 44 |
| 6 | 265 |
| 7 | 1280 |
| 8 | 5289 |
| 9 | 20366 |
| 10 | 78092 |
| 11 | 307978 |
| 12 | 1268773 |
| 13 | 5312280 |
| 14 | 22254973 |
| 15 | 92569648 |
| 16 | 381758301 |
| 17 | 1565720382 |
| 18 | 6420604761 |
| 19 | 26380036552 |
| 20 | 108607137785 |
| 21 | 447677119208 |
| 22 | 1845681472072 |
| 23 | 7605764624216 |
| 24 | 31326172589888 |
| 25 | 128986886647264 |
| 26 | 531083492316608 |