A012387 Duplicate of A009518.
0, 2, 16, 152, -5504, -1107808, -155757824, -22741022848, -3557729644544
Offset: 0
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.