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 | -492 |
| 2 | -22590 |
| 3 | -367400 |
| 4 | -3764865 |
| 5 | -28951452 |
| 6 | -182474434 |
| 7 | -990473160 |
| 8 | -4780921725 |
| 9 | -20974230680 |
| 10 | -84963769662 |
| 11 | -321583404672 |
| 12 | -1147744866180 |
| 13 | -3890805976500 |
| 14 | -12601590210180 |
| 15 | -39183052547592 |
| 16 | -117437602167291 |
| 17 | -340431109329600 |
| 18 | -957251463332600 |
| 19 | -2617490612355240 |
| 20 | -6975126788952456 |
| 21 | -18149106017123576 |
| 22 | -46187557595906250 |