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 | 0 |
| 2 | 6 |
| 3 | -12 |
| 4 | -156 |
| 5 | 1680 |
| 6 | 21264 |
| 7 | -592032 |
| 8 | -5349216 |
| 9 | 381679872 |
| 10 | 1095380736 |
| 11 | -384803443200 |
| 12 | 2445989918208 |
| 13 | 547003852781568 |