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 | -4 |
| 2 | 0 |
| 3 | -8 |
| 4 | -76 |
| 5 | -752 |
| 6 | -8460 |
| 7 | -107520 |
| 8 | -1522124 |
| 9 | -23717424 |
| 10 | -402941324 |
| 11 | -7407988448 |
| 12 | -146479479308 |
| 13 | -3099229422352 |
| 14 | -69863683041868 |
| 15 | -1671667534710720 |
| 16 | -42318672085310540 |
| 17 | -1130167625049525232 |
| 18 | -31758424368739424780 |
| 19 | -936840101208573355680 |