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 | 1 |
| 2 | 18 |
| 3 | 486 |
| 4 | 17496 |
| 5 | 787320 |
| 6 | 42515280 |
| 7 | 2678462640 |
| 8 | 192849310080 |
| 9 | 15620794116480 |
| 10 | 1405871470483200 |
| 11 | 139181275577836800 |
| 12 | 15031577762406374400 |
| 13 | 1758694598201545804800 |
| 14 | 221595519373394771404800 |
| 15 | 29915395115408294139648000 |
| 16 | 4307816896618794356109312000 |