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 | 1 |
| 5 | 1 |
| 6 | 15 |
| 7 | 455 |
| 8 | 20230 |
| 9 | 1166886 |
| 10 | 82031250 |
| 11 | 6768679170 |
| 12 | 639276644655 |
| 13 | 67876292150095 |
| 14 | 7992910154350121 |
| 15 | 1032869077119140625 |
| 16 | 145221924661653841820 |
| 17 | 22060305511905816000860 |
| 18 | 3599313659344525384083060 |
| 19 | 627583654087024080928783956 |