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 | -2 |
| 3 | 8 |
| 4 | -47 |
| 5 | 359 |
| 6 | -3349 |
| 7 | 36756 |
| 8 | -462972 |
| 9 | 6574704 |
| 10 | -103861896 |
| 11 | 1805930928 |
| 12 | -34267701720 |
| 13 | 704555489832 |
| 14 | -15601914340440 |
| 15 | 370195510608192 |
| 16 | -9369769657984128 |
| 17 | 251979258929744448 |
| 18 | -7175127496412091456 |