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 | 3 |
| 4 | 28 |
| 5 | 765 |
| 6 | 26958 |
| 7 | 1887277 |
| 8 | 252458904 |
| 9 | 66376420155 |
| 10 | 34508978662350 |
| 11 | 35645504882731557 |
| 12 | 73356937843604425644 |
| 13 | 301275024444053951967585 |
| 14 | 2471655539736990372520379226 |
| 15 | 40527712706903544100966076156895 |
| 16 | 1328579255614092949957261201822704816 |