A365651 Number of fixed n-polyominoids, allowing both corner- and edge-connections.
3, 48, 1072, 27732, 781200
Offset: 1
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.