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 | 3 |
| 3 | 19 |
| 4 | 245 |
| 5 | 4751 |
| 6 | 124936 |
| 7 | 4141383 |
| 8 | 166237161 |
| 9 | 7847250409 |
| 10 | 426342182761 |
| 11 | 26219808548110 |
| 12 | 1801378010581175 |
| 13 | 136784412621194274 |
| 14 | 11378390032696241010 |
| 15 | 1029218687419565103111 |
| 16 | 100592759623604055645649 |
| 17 | 10565465772302876757883823 |
| 18 | 1186893721789951847976898669 |