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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 2 |
| 7 | 8 |
| 8 | 115 |
| 9 | 1274 |
| 10 | 15099 |
| 11 | 179628 |
| 12 | 2260064 |
| 13 | 30534802 |
| 14 | 441269110 |
| 15 | 6789665680 |
| 16 | 110947884520 |
| 17 | 1920180939650 |
| 18 | 35099424286573 |
| 19 | 675866037989156 |
| 20 | 13676799446869485 |
| 21 | 290208293166279344 |
| 22 | 6443880771921767240 |