A361525 Number of ways of dividing an n X 3 rectangle into integer-sided rectangles, up to rotations and reflections.
1, 3, 17, 54, 892, 8159, 80021, 791821, 7906439, 79069308
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.