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) |
|---|---|
| 2 | 1 |
| 3 | 9 |
| 4 | 107 |
| 5 | 1650 |
| 6 | 31594 |
| 7 | 725592 |
| 8 | 19471500 |
| 9 | 598482000 |
| 10 | 20742534576 |
| 11 | 800575997760 |
| 12 | 34059828307680 |
| 13 | 1583808130195200 |
| 14 | 79925022369273600 |
| 15 | 4350478314951982080 |
| 16 | 254086498336122950400 |
| 17 | 15849890120755311667200 |