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 | 1 |
| 3 | 4 |
| 4 | 13 |
| 5 | 61 |
| 6 | 331 |
| 7 | 1996 |
| 8 | 14449 |
| 9 | 109873 |
| 10 | 971821 |
| 11 | 8995636 |
| 12 | 93329941 |
| 13 | 1018571269 |
| 14 | 12110589583 |
| 15 | 151955795356 |
| 16 | 2037757374241 |
| 17 | 28837620752161 |
| 18 | 430834395468889 |
| 19 | 6777014821152868 |
| 20 | 111663525724783741 |
| 21 | 1930478057636642221 |
| 22 | 34781068833200111731 |