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 | 0 |
| 2 | -4 |
| 3 | 36 |
| 4 | 129 |
| 5 | 3340 |
| 6 | 2287607 |
| 7 | 162104000 |
| 8 | 16943055268 |
| 9 | 4059346088384 |
| 10 | 474967482901952 |
| 11 | 221630954408019520 |