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 | 12 |
| 3 | -45 |
| 4 | 1404 |
| 5 | -33048 |
| 6 | 684288 |
| 7 | -5847309 |
| 8 | -440129376 |
| 9 | 30809872071 |
| 10 | -952939532952 |
| 11 | -1846906652457 |
| 12 | 1545045542366472 |
| 13 | -30949156972076031 |
| 14 | -4367665752590389608 |
| 15 | 253458876292612253442 |
| 16 | 14695464346775699515704 |
| 17 | -2012792131604632851142020 |