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) |
|---|---|
| 1 | -1 |
| 2 | -2 |
| 3 | -7 |
| 4 | -40 |
| 5 | -301 |
| 6 | -2856 |
| 7 | -32299 |
| 8 | -416816 |
| 9 | -5892345 |
| 10 | -86464000 |
| 11 | -1177909711 |
| 12 | -8944121088 |
| 13 | 349846341467 |
| 14 | 29237270702080 |
| 15 | 1585383533246925 |
| 16 | 78578098584541184 |
| 17 | 3843296406581515919 |
| 18 | 190784066705549623296 |