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 | 0 |
| 2 | 3 |
| 3 | -4 |
| 4 | 11 |
| 5 | -24 |
| 6 | 55 |
| 7 | -124 |
| 8 | 283 |
| 9 | -640 |
| 10 | 1455 |
| 11 | -3300 |
| 12 | 7491 |
| 13 | -17000 |
| 14 | 38583 |
| 15 | -87564 |
| 16 | 198731 |
| 17 | -451024 |
| 18 | 1023615 |
| 19 | -2323124 |
| 20 | 5272403 |
| 21 | -11965880 |
| 22 | 27156935 |
| 23 | -61633500 |
| 24 | 139879131 |
| 25 | -317460000 |
| 26 | 720485263 |
| 27 | -1635163524 |
| 28 | 3711054051 |
| 29 | -8422351624 |
| 30 | 19114786775 |
| 31 | -43381598124 |
| 32 | 98455874923 |