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 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 1 |
| 6 | 1365 |
| 7 | 290745 |
| 8 | 35804384 |
| 9 | 3431889000 |
| 10 | 288982989000 |
| 11 | 22716104811840 |
| 12 | 1724903317684800 |
| 13 | 129165517275377154 |
| 14 | 9664573656742964960 |
| 15 | 728813888470620552600 |
| 16 | 55713446610261097382400 |
| 17 | 4334305420045397178746260 |
| 18 | 344080024970397555374419968 |
| 19 | 27923503603736889921687649020 |