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 | 2 |
| 4 | 10 |
| 5 | 56 |
| 6 | 477 |
| 7 | 5879 |
| 8 | 117729 |
| 9 | 4014125 |
| 10 | 242887444 |
| 11 | 26562628943 |
| 12 | 5300430360196 |
| 13 | 1941457570816837 |
| 14 | 1311926679135555495 |
| 15 | 1643205542452252078848 |
| 16 | 3831756372376104769454402 |
| 17 | 16704363592309800046798746041 |
| 18 | 136665888984665718748205681747780 |