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 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 37 |
| 5 | 268 |
| 6 | 2496 |
| 7 | 28612 |
| 8 | 391189 |
| 9 | 6230646 |
| 10 | 113521387 |
| 11 | 2332049710 |
| 12 | 53384167192 |
| 13 | 1348601249480 |
| 14 | 37291381915789 |
| 15 | 1120914133433121 |
| 16 | 36406578669907180 |
| 17 | 1271084987848923282 |
| 18 | 47487293697623885913 |
| 19 | 1890771531272515677250 |
| 20 | 79947079338974990793060 |