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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.

A318270 a(n) is the number of configurations of n indistinguishable pairs placed on the vertices of the ladder graph P_2 X P_n such that all but 5 such pairs are joined by an edge.

Table of values

n a(n)
0 0
1 0
2 0
3 0
4 0
5 186
6 3666
7 36714
8 253386
9 1369260
10 6209700
11 24668742
12 88338174
13 290968686
14 894709790
15 2597386330
16 7181246394
17 19040425628
18 48684375292
19 120592523460
20 290476059204
21 682548818802
22 1568744083242
23 3534725236308
24 7823387477220
25 17037467831748

List of values

[0, 0, 0, 0, 0, 186, 3666, 36714, 253386, 1369260, 6209700, 24668742, 88338174, 290968686, 894709790, 2597386330, 7181246394, 19040425628, 48684375292, 120592523460, 290476059204, 682548818802, 1568744083242, 3534725236308, 7823387477220, 17037467831748]

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

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