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 | -6 |
| 4 | 35 |
| 5 | 87 |
| 6 | -588 |
| 7 | -1578 |
| 8 | 11511 |
| 9 | 32223 |
| 10 | -245883 |
| 11 | -706824 |
| 12 | 5556564 |
| 13 | 16267508 |
| 14 | -130617600 |
| 15 | -387533058 |
| 16 | 3161190783 |
| 17 | 9474886287 |
| 18 | -78241316361 |
| 19 | -236394953670 |
| 20 | 1971270824859 |
| 21 | 5994591989967 |
| 22 | -50388913722480 |
| 23 | -154052058035736 |