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 | -2 |
| 3 | 2 |
| 4 | -32 |
| 5 | 64 |
| 6 | -464 |
| 7 | 3968 |
| 8 | -92672 |
| 9 | 414720 |
| 10 | -5486592 |
| 11 | 68247552 |
| 12 | -869895168 |
| 13 | 15949529088 |
| 14 | -299609505792 |
| 15 | 5012834549760 |
| 16 | -177156842717184 |
| 17 | 2119956936523776 |
| 18 | -50954009373573120 |
| 19 | 1123874181449515008 |
| 20 | -29311973327486582784 |
| 21 | 730049769522063212544 |
| 22 | -22005690087484302557184 |