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 | 3 |
| 3 | 4 |
| 4 | 9 |
| 5 | -24 |
| 6 | -143 |
| 7 | -902 |
| 8 | -1631 |
| 9 | 5176 |
| 10 | 109841 |
| 11 | 664302 |
| 12 | 1479841 |
| 13 | -16079764 |
| 14 | -240229975 |
| 15 | -1395162974 |
| 16 | 126628545 |
| 17 | 101950486736 |
| 18 | 1118811398113 |
| 19 | 4468008939542 |
| 20 | -46600859353919 |
| 21 | -1019505781080044 |
| 22 | -7952038289388071 |
| 23 | 10041106628453162 |