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 | 1 |
| 3 | 0 |
| 4 | -9 |
| 5 | 80 |
| 6 | 6111 |
| 7 | 29951360 |
| 8 | -207256402585089 |
| 9 | -3919788933040280447085605363200 |
| 10 | 14683863149476410414382246646213355893861151824423487368369151 |