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 | -3 |
| 3 | -11 |
| 4 | 25 |
| 5 | 41 |
| 6 | -43 |
| 7 | 29 |
| 8 | -335 |
| 9 | -1199 |
| 10 | 3117 |
| 11 | 6469 |
| 12 | -10295 |
| 13 | -8839 |
| 14 | -16123 |
| 15 | -108691 |
| 16 | 354145 |
| 17 | 873121 |
| 18 | -1721763 |
| 19 | -2521451 |
| 20 | 1476985 |
| 21 | -6699319 |
| 22 | 34182197 |
| 23 | 103232189 |
| 24 | -242017775 |
| 25 | -451910159 |
| 26 | 597551757 |
| 27 | 130656229 |
| 28 | 2465133865 |
| 29 | 10513816601 |
| 30 | -29729597083 |
| 31 | -66349305331 |