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 | 0 |
| 3 | -16 |
| 4 | 80 |
| 5 | -4640 |
| 6 | -1696 |
| 7 | -47290368 |
| 8 | 778240 |
| 9 | -1252408320 |
| 10 | 827269120 |
| 11 | -1883587535170560 |
| 12 | -167527809024 |
| 13 | -660985839681085440 |
| 14 | -66300178824585216 |
| 15 | -1744375183677849600 |
| 16 | 29157688117836220727296 |
| 17 | 5544673967679230591621398528 |
| 18 | -134078707495836661579776 |