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 | 3 |
| 3 | 105 |
| 4 | 4620 |
| 5 | 283500 |
| 6 | 23700600 |
| 7 | 2610808200 |
| 8 | 367783416000 |
| 9 | 64607286744000 |
| 10 | 13859305059600000 |
| 11 | 3567385122341040000 |
| 12 | 1085582734152396480000 |
| 13 | 385634331725066424000000 |
| 14 | 158175715893528308976000000 |
| 15 | 74203019661816956710800000000 |
| 16 | 39481403043334753112451840000000 |