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 | 0 |
| 3 | 1 |
| 4 | 3 |
| 5 | 4 |
| 6 | 15 |
| 7 | 33 |
| 8 | 111 |
| 9 | 382 |
| 10 | 1195 |
| 11 | 3366 |
| 12 | 14077 |
| 13 | 53265 |
| 14 | 229603 |
| 15 | 910254 |
| 16 | 4524029 |
| 17 | 18879944 |
| 18 | 91336498 |
| 19 | 561832582 |
| 20 | 2801857644 |
| 21 | 14652294729 |
| 22 | 78894985156 |
| 23 | 408373652461 |
| 24 | 2378940665083 |
| 25 | 11939275822636 |
| 26 | 71931330299023 |
| 27 | 392274481206066 |
| 28 | 2626331088771946 |