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 | -2 |
| 3 | 13 |
| 4 | -98 |
| 5 | 826 |
| 6 | -7448 |
| 7 | 70309 |
| 8 | -686090 |
| 9 | 6865150 |
| 10 | -70057772 |
| 11 | 726325810 |
| 12 | -7628741204 |
| 13 | 81002393668 |
| 14 | -868066319108 |
| 15 | 9376806129493 |
| 16 | -101988620430938 |
| 17 | 1116026661667318 |
| 18 | -12277755319108748 |
| 19 | 135715825209716038 |
| 20 | -1506587474535945788 |
| 21 | 16789107646422189868 |
| 22 | -187747069029477151328 |