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) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 9 |
| 5 | 648 |
| 6 | 57600 |
| 7 | 6615000 |
| 8 | 972504225 |
| 9 | 179499220992 |
| 10 | 40789783609344 |
| 11 | 11212877910528000 |
| 12 | 3671848787797265625 |
| 13 | 1413385410212064432000 |
| 14 | 632129969391038455873536 |
| 15 | 325176984737061807515098752 |
| 16 | 190691488202627199302740850625 |
| 17 | 126479088749202444199526400000000 |