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 | 0 |
| 1 | 1 |
| 2 | 4 |
| 3 | 2 |
| 4 | 12 |
| 5 | -30 |
| 6 | 24 |
| 7 | 1412 |
| 8 | -18716 |
| 9 | 127750 |
| 10 | -19448 |
| 11 | -10721556 |
| 12 | 98983992 |
| 13 | 546122580 |
| 14 | -19718580272 |
| 15 | 30721006440 |
| 16 | 4638904011364 |
| 17 | -44204880124922 |
| 18 | -1218793973236472 |
| 19 | 26364933421291468 |
| 20 | 327900715232299304 |
| 21 | -15425392878552410820 |
| 22 | -62258050574118828336 |