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 | 4 |
| 2 | -20 |
| 3 | -216 |
| 4 | 2025 |
| 5 | 24457 |
| 6 | -661745 |
| 7 | -21930489 |
| 8 | 485222400 |
| 9 | 12094491106 |
| 10 | -594800640896 |
| 11 | -32850150466188 |
| 12 | 1138086428486400 |
| 13 | 42791463719713975 |
| 14 | -3042278237035388153 |
| 15 | -123027745203325414816 |
| 16 | 5708406518410582200000 |
| 17 | 275201338468042020170179 |