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 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | 4 |
| 6 | 8 |
| 7 | 37 |
| 8 | 184 |
| 9 | 1782 |
| 10 | 31026 |
| 11 | 1148626 |
| 12 | 86539128 |
| 13 | 12798435868 |
| 14 | 3620169692289 |
| 15 | 1940367005824561 |
| 16 | 1965937435288738165 |
| 17 | 3766548132138130650270 |
| 18 | 13666503289976224080346733 |