A089431 Even-indexed terms of A089423.
1, 2, 12, 120, 840, 5040, 55440, 720720, 720720, 24504480, 465585120
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.