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 | 0 |
| 1 | -1 |
| 2 | 80 |
| 3 | -4016 |
| 4 | 190465 |
| 5 | -8960160 |
| 6 | 421021536 |
| 7 | -19779631105 |
| 8 | 929225609456 |
| 9 | -43653851217680 |
| 10 | 2050801968082945 |
| 11 | -96344039926706496 |
| 12 | 4526119083346841280 |
| 13 | -212631252937414840321 |
| 14 | 9989142769386670981520 |
| 15 | -469277078911056723578480 |