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) |
|---|---|
| 2 | 1 |
| 3 | -3 |
| 4 | 31 |
| 5 | -375 |
| 6 | 5911 |
| 7 | -113463 |
| 8 | 2571031 |
| 9 | -67170855 |
| 10 | 1987919671 |
| 11 | -65731585623 |
| 12 | 2401646633431 |
| 13 | -96089053104135 |
| 14 | 4178215255335031 |
| 15 | -196193483904124983 |
| 16 | 9894077286353278231 |
| 17 | -533334378459657706215 |
| 18 | 30602112192036616407991 |