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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.

A385381 Triangle read by rows: T(n,k) is the number of polyominoes, i.e., connected nonempty subsets of square cells (or vertices), of the n X k flat torus, up to cyclic shifts and reflections of rows and columns; 1 <= k <= n.

Table of values

n a(n)
1 1
2 2
3 5
4 3
5 10
6 28
7 4
8 21
9 102
10 801
11 5
12 40
13 382
14 6790
15 129550
16 6
17 86
18 1788
19 68569
20 2694721

List of values

[1, 2, 5, 3, 10, 28, 4, 21, 102, 801, 5, 40, 382, 6790, 129550, 6, 86, 1788, 68569, 2694721]

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

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