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 | 1 |
| 1 | -1 |
| 2 | -1 |
| 3 | 3 |
| 4 | 1 |
| 5 | 17 |
| 6 | -119 |
| 7 | 165 |
| 8 | 1191 |
| 9 | -21989 |
| 10 | 169527 |
| 11 | -317837 |
| 12 | -7182779 |
| 13 | 54452161 |
| 14 | 292654649 |
| 15 | -4320853051 |
| 16 | -46883217705 |
| 17 | 728176373539 |
| 18 | 9943868087879 |
| 19 | -166076498591597 |
| 20 | -2748733072385043 |
| 21 | 65290726021558089 |
| 22 | 151614363753006601 |
| 23 | -11661992771499644571 |