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 | 4 |
| 2 | -1042 |
| 3 | -12632 |
| 4 | 3256780 |
| 5 | 66485744 |
| 6 | -16962423224 |
| 7 | -489901195808 |
| 8 | 123664101613712 |
| 9 | 4641180127773760 |
| 10 | -1158964855054670624 |
| 11 | -53739545172065063296 |
| 12 | 13273074802437996468928 |
| 13 | 735369564714290029481728 |
| 14 | -179616392573875043315708800 |
| 15 | -11610759562843564089946190336 |