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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.

A268339 Number of polyominoes with width and height equal to n that are invariant under all symmetries of the square.

Table of values

n a(n)
1 1
2 1
3 3
4 3
5 17
6 17
7 163
8 163
9 2753
10 2753
11 84731
12 84731
13 4879497
14 4879497
15 535376723
16 535376723
17 112921823249
18 112921823249
19 45931435159067
20 45931435159067
21 36048888105745113
22 36048888105745113
23 54568015172025197171
24 54568015172025197171
25 159197415409641803530753
26 159197415409641803530753

List of values

[1, 1, 3, 3, 17, 17, 163, 163, 2753, 2753, 84731, 84731, 4879497, 4879497, 535376723, 535376723, 112921823249, 112921823249, 45931435159067, 45931435159067, 36048888105745113, 36048888105745113, 54568015172025197171, 54568015172025197171, 159197415409641803530753, 159197415409641803530753]

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

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