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) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 9 |
| 6 | 22 |
| 7 | 52 |
| 8 | 140 |
| 9 | 340 |
| 10 | 969 |
| 11 | 2394 |
| 12 | 7084 |
| 13 | 17710 |
| 14 | 53820 |
| 15 | 135720 |
| 16 | 420732 |
| 17 | 1068012 |
| 18 | 3362260 |
| 19 | 8579560 |
| 20 | 27343888 |
| 21 | 70068713 |
| 22 | 225568798 |
| 23 | 580034052 |
| 24 | 1882933364 |
| 25 | 4855986044 |
| 26 | 15875338990 |
| 27 | 41043559340 |
| 28 | 134993766600 |