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 | 1 |
| 3 | 1 |
| 4 | 9 |
| 5 | 36 |
| 6 | 571 |
| 7 | 12465 |
| 8 | 543116 |
| 9 | 35241608 |
| 10 | 3230417239 |
| 11 | 397514307014 |
| 12 | 63830872225605 |
| 13 | 13080448625309965 |
| 14 | 3358687593761378470 |
| 15 | 1063838242661288090062 |
| 16 | 410057057694777406364151 |
| 17 | 190064879184725871853627854 |
| 18 | 104825763290631293396894238206 |