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 | -2 |
| 4 | -11 |
| 5 | -24 |
| 6 | 61 |
| 7 | 624 |
| 8 | 1737 |
| 9 | -7424 |
| 10 | -88679 |
| 11 | -242560 |
| 12 | 2086525 |
| 13 | 23499776 |
| 14 | 45950997 |
| 15 | -1002251264 |
| 16 | -9763133167 |
| 17 | -2151563264 |
| 18 | 705668046769 |
| 19 | 5583112077312 |
| 20 | -17356978593659 |
| 21 | -666018502836224 |
| 22 | -3823112141007763 |
| 23 | 39230927775531008 |
| 24 | 788728947108214489 |