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 | -4 |
| 3 | 0 |
| 4 | 20 |
| 5 | -25 |
| 6 | -71 |
| 7 | 216 |
| 8 | 94 |
| 9 | -1220 |
| 10 | 1037 |
| 11 | 4941 |
| 12 | -11440 |
| 13 | -11008 |
| 14 | 72112 |
| 15 | -33453 |
| 16 | -326675 |
| 17 | 577060 |
| 18 | 950750 |
| 19 | -4129272 |
| 20 | 279257 |
| 21 | 20740793 |
| 22 | -27217100 |
| 23 | -72078336 |
| 24 | 228625372 |
| 25 | 83808415 |
| 26 | -1271796511 |
| 27 | 1153458144 |
| 28 | 5060707454 |
| 29 | -12183603100 |
| 30 | -10694679515 |
| 31 | 75519944325 |
| 32 | -39290857304 |
| 33 | -336819940736 |