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 | 15 |
| 4 | -124 |
| 5 | 1285 |
| 6 | -16026 |
| 7 | 233135 |
| 8 | -3875768 |
| 9 | 72487593 |
| 10 | -1506355510 |
| 11 | 34433714755 |
| 12 | -858675022932 |
| 13 | 23197217353661 |
| 14 | -674881675961234 |
| 15 | 21036941762791575 |
| 16 | -699465496639029616 |
| 17 | 24710351707159115089 |
| 18 | -924304656631807218798 |
| 19 | 36494922945480344959595 |