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 | 12 |
| 2 | -60 |
| 3 | 768 |
| 4 | -11004 |
| 5 | 178200 |
| 6 | -3093504 |
| 7 | 56265216 |
| 8 | -1058194428 |
| 9 | 20410970124 |
| 10 | -401553531000 |
| 11 | 8026398749952 |
| 12 | -162541338390528 |
| 13 | 3327702330562584 |
| 14 | -68761528402925568 |
| 15 | 1432192515405350400 |
| 16 | -30037109244686774268 |
| 17 | 633790586271852392472 |
| 18 | -13444940755220756447292 |
| 19 | 286577646482211381212928 |