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 | -18 |
| 4 | -32 |
| 5 | -75 |
| 6 | 1188 |
| 7 | 2205 |
| 8 | 7936 |
| 9 | 19278 |
| 10 | 49500 |
| 11 | 87120 |
| 12 | 185760 |
| 13 | 312988 |
| 14 | 574868 |
| 15 | -10481175 |
| 16 | -15271936 |
| 17 | -46022672 |
| 18 | -98470404 |
| 19 | -230150496 |
| 20 | -440484000 |
| 21 | -932930208 |
| 22 | -1572331596 |
| 23 | -2940575576 |
| 24 | -4940815104 |
| 25 | -8508211250 |
| 26 | -13542949524 |
| 27 | -22406625648 |