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) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | -8 |
| 5 | 28 |
| 6 | -26 |
| 7 | -386 |
| 8 | 2701 |
| 9 | -5399 |
| 10 | -42155 |
| 11 | 358615 |
| 12 | -354212 |
| 13 | -10419524 |
| 14 | 52825312 |
| 15 | 236952352 |
| 16 | -3103798967 |
| 17 | -3013742105 |
| 18 | 176201013745 |
| 19 | -164790760103 |
| 20 | -11763898514324 |
| 21 | 27830312919316 |
| 22 | 992172068848126 |
| 23 | -3681957974446718 |
| 24 | -103284064687144985 |
| 25 | 528045230825074855 |