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) |
|---|---|
| 8 | 1 |
| 9 | 8 |
| 10 | 72 |
| 11 | 600 |
| 12 | 5280 |
| 13 | 48312 |
| 14 | 465036 |
| 15 | 4708704 |
| 16 | 50160825 |
| 17 | 561623920 |
| 18 | 6600378928 |
| 19 | 81297463104 |
| 20 | 1047817553016 |
| 21 | 14109488456400 |
| 22 | 198192170408400 |
| 23 | 2899804394683680 |
| 24 | 44131025207930595 |
| 25 | 697636040687261280 |
| 26 | 11441167306954104500 |
| 27 | 194421818718469399200 |