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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.

A216492 Number of inequivalent connected planar figures that can be formed from n 1 X 2 rectangles (or dominoes) such that each pair of touching rectangles shares exactly one edge, of length 1, and the adjacency graph of the rectangles is a tree.

Table of values

n a(n)
0 1
1 1
2 3
3 18
4 139
5 1286
6 12715
7 130875
8 1378139
9 14752392
10 159876353
11 1749834718
12 19307847070

List of values

[1, 1, 3, 18, 139, 1286, 12715, 130875, 1378139, 14752392, 159876353, 1749834718, 19307847070]

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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