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 | 1 |
| 6 | -1 |
| 7 | 1 |
| 8 | -1 |
| 9 | 1 |
| 10 | 5 |
| 11 | -12 |
| 12 | 20 |
| 13 | -29 |
| 14 | 39 |
| 15 | 1 |
| 16 | -109 |
| 17 | 305 |
| 18 | -611 |
| 19 | 1051 |
| 20 | -1145 |
| 21 | 139 |
| 22 | 3055 |
| 23 | -9924 |
| 24 | 22424 |
| 25 | -37574 |
| 26 | 43476 |
| 27 | -14035 |
| 28 | -97831 |
| 29 | 368715 |
| 30 | -852385 |
| 31 | 1470767 |
| 32 | -1823523 |
| 33 | 885634 |
| 34 | 3444224 |
| 35 | -14239745 |
| 36 | 34089723 |
| 37 | -61051093 |
| 38 | 80200515 |
| 39 | -48234695 |
| 40 | -123155951 |