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 | 3 |
| 4 | 11 |
| 5 | 51 |
| 6 | 281 |
| 7 | 1809 |
| 8 | 13293 |
| 9 | 109899 |
| 10 | 1009343 |
| 11 | 10196895 |
| 12 | 112375149 |
| 13 | 1341625041 |
| 14 | 17249416717 |
| 15 | 237618939975 |
| 16 | 3491542594727 |
| 17 | 54510993341523 |
| 18 | 901106621474801 |
| 19 | 15723571927404189 |
| 20 | 288804851413993941 |
| 21 | 5569918636750820751 |
| 22 | 112537773142244706427 |