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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | -2 |
| 5 | -22 |
| 6 | -23 |
| 7 | 1614 |
| 8 | 21952 |
| 9 | 200754 |
| 10 | 1427826 |
| 11 | 6969680 |
| 12 | -2536429 |
| 13 | -648528610 |
| 14 | -11247293516 |
| 15 | -143493754330 |
| 16 | -1578026921839 |
| 17 | -15633412845816 |
| 18 | -140582270611489 |
| 19 | -1122913035234416 |
| 20 | -7326349588043722 |
| 21 | -25245049578998081 |
| 22 | 301375487087871682 |
| 23 | 9140885960557495580 |
| 24 | 157255672291012140238 |
| 25 | 2265259467069624459434 |