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 | 5 |
| 3 | 32 |
| 4 | 237 |
| 5 | 1906 |
| 6 | 16179 |
| 7 | 142665 |
| 8 | 1294115 |
| 9 | 11998349 |
| 10 | 113194205 |
| 11 | 1083131419 |
| 12 | 10486939473 |
| 13 | 102548233212 |
| 14 | 1011333385507 |
| 15 | 10047289999536 |
| 16 | 100458873883179 |
| 17 | 1010138430187185 |
| 18 | 10208244014494347 |
| 19 | 103625607305637693 |
| 20 | 1056166710786300973 |