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) |
|---|---|
| 2 | 1 |
| 3 | 3 |
| 4 | 8 |
| 5 | 25 |
| 6 | 108 |
| 7 | 735 |
| 8 | 4608 |
| 9 | 40824 |
| 10 | 362000 |
| 11 | 3628185 |
| 12 | 40766976 |
| 13 | 478988081 |
| 14 | 6227101888 |
| 15 | 87146087625 |
| 16 | 1300561920000 |
| 17 | 20922788404479 |
| 18 | 355737629952000 |
| 19 | 6402373698206889 |
| 20 | 121810906419200000 |
| 21 | 2432822933484213543 |
| 22 | 51090942172652090368 |
| 23 | 1124000727778962143055 |