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 | 3 |
| 2 | 10 |
| 3 | 41 |
| 4 | 172 |
| 5 | 749 |
| 6 | 3332 |
| 7 | 15041 |
| 8 | 68640 |
| 9 | 315840 |
| 10 | 1462798 |
| 11 | 6810588 |
| 12 | 31846811 |
| 13 | 149459541 |
| 14 | 703592472 |
| 15 | 3321019270 |
| 16 | 15711717162 |
| 17 | 74482623635 |
| 18 | 353723268817 |
| 19 | 1682536854931 |
| 20 | 8014676326925 |
| 21 | 38226681972410 |
| 22 | 182538225520073 |