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 | 1 |
| 3 | -1 |
| 4 | -11 |
| 5 | -33 |
| 6 | 61 |
| 7 | 1367 |
| 8 | 7253 |
| 9 | -12561 |
| 10 | -580499 |
| 11 | -4701497 |
| 12 | 4669765 |
| 13 | 580325215 |
| 14 | 6636339165 |
| 15 | 1365901495 |
| 16 | -1122870368715 |
| 17 | -17289945450289 |
| 18 | -31110588453299 |
| 19 | 3713822629274023 |
| 20 | 74717183313957413 |
| 21 | 280555705771423039 |
| 22 | -19253195126787261507 |
| 23 | -496715617694137066089 |
| 24 | -3008746115751273626347 |