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 | 0 |
| 4 | -15 |
| 5 | -99 |
| 6 | -398 |
| 7 | -1175 |
| 8 | -2351 |
| 9 | 0 |
| 10 | 29601 |
| 11 | 183195 |
| 12 | 756978 |
| 13 | 2351805 |
| 14 | 4885791 |
| 15 | 0 |
| 16 | -63746991 |
| 17 | -400000275 |
| 18 | -1675991918 |
| 19 | -5274560891 |
| 20 | -11081420615 |
| 21 | 0 |
| 22 | 147257373891 |
| 23 | 931226954949 |
| 24 | 3929550225586 |
| 25 | 12446852889901 |
| 26 | 26304183607651 |
| 27 | 0 |
| 28 | -353181028924809 |