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) |
|---|---|
| 4 | 1 |
| 5 | 48 |
| 6 | 1728 |
| 7 | 62720 |
| 8 | 2457600 |
| 9 | 105815808 |
| 10 | 5017600000 |
| 11 | 261227298816 |
| 12 | 14860167413760 |
| 13 | 918839084134400 |
| 14 | 61439672177393700 |
| 15 | 4421589120000000000 |
| 16 | 340976534987475000000 |
| 17 | 28064307240230900000000 |
| 18 | 2456376885785930000000000 |