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 | 0 |
| 2 | 2 |
| 3 | 24 |
| 4 | 194 |
| 5 | 1320 |
| 6 | 8162 |
| 7 | 47544 |
| 8 | 266114 |
| 9 | 1448520 |
| 10 | 7727522 |
| 11 | 40616664 |
| 12 | 211117634 |
| 13 | 1088079720 |
| 14 | 5571427682 |
| 15 | 28384443384 |
| 16 | 144041002754 |
| 17 | 728708854920 |
| 18 | 3677645732642 |
| 19 | 18524892775704 |
| 20 | 93171895169474 |
| 21 | 468051525534120 |
| 22 | 2349032799986402 |