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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 2 |
| 7 | 0 |
| 8 | 0 |
| 9 | 0 |
| 10 | 6 |
| 11 | 6 |
| 12 | -8 |
| 13 | 0 |
| 14 | 36 |
| 15 | 36 |
| 16 | -42 |
| 17 | -60 |
| 18 | 272 |
| 19 | 330 |
| 20 | -402 |
| 21 | -554 |
| 22 | 1758 |
| 23 | 3564 |
| 24 | -3320 |
| 25 | -7056 |
| 26 | 14616 |
| 27 | 33426 |
| 28 | -21498 |
| 29 | -83640 |
| 30 | 111856 |
| 31 | 354612 |
| 32 | -158802 |
| 33 | -884208 |
| 34 | 758088 |
| 35 | 3744582 |
| 36 | -734260 |
| 37 | -9805608 |
| 38 | 4839270 |
| 39 | 38734736 |
| 40 | 2364180 |