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 | 1 |
| 3 | 21 |
| 4 | 552 |
| 5 | 19560 |
| 6 | 920160 |
| 7 | 55974240 |
| 8 | 4293596160 |
| 9 | 406306575360 |
| 10 | 46556342784000 |
| 11 | 6357567896064000 |
| 12 | 1020650937901056000 |
| 13 | 190386526063878144000 |
| 14 | 40844355820490686464000 |
| 15 | 9987985777548364185600000 |
| 16 | 2762125829379285162393600000 |
| 17 | 857790151281459139077734400000 |