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) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | -1 |
| 4 | 0 |
| 5 | -17 |
| 6 | 0 |
| 7 | -1955 |
| 8 | 0 |
| 9 | -44089 |
| 10 | 0 |
| 11 | -4627969 |
| 12 | 0 |
| 13 | -10431967727 |
| 14 | 0 |
| 15 | -424734574531 |
| 16 | 0 |
| 17 | -187497600357613 |
| 18 | 0 |
| 19 | -263146180762981877 |
| 20 | 0 |
| 21 | -77335840394370605087 |
| 22 | 0 |
| 23 | -38414950218116664660463 |
| 24 | 0 |
| 25 | -95193934978797641162562791 |
| 26 | 0 |
| 27 | -1044549307308161782597280065 |
| 28 | 0 |
| 29 | -836232289988098415162220532417 |