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 | 2 |
| 4 | 6 |
| 5 | 30 |
| 6 | 221 |
| 7 | 2201 |
| 8 | 27769 |
| 9 | 424757 |
| 10 | 7639190 |
| 11 | 157969167 |
| 12 | 3692733181 |
| 13 | 96293669499 |
| 14 | 2771232779481 |
| 15 | 87247362424120 |
| 16 | 2982901522141490 |
| 17 | 110057420712635526 |
| 18 | 4358745145279372293 |
| 19 | 184433423940319376323 |