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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.

A318267 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 two such pairs are joined by an edge.

Table of values

n a(n)
0 0
1 0
2 1
3 8
4 39
5 138
6 414
7 1104
8 2715
9 6282
10 13875
11 29540
12 61060
13 123192
14 243589
15 473540
16 907335
17 1716974
18 3214066
19 5959704
20 10958687
21 20001526
22 36264579
23 65359752
24 117165096
25 209008464
26 371190217
27 656540768
28 1156924167
29 2031676818
30 3556517478

List of values

[0, 0, 1, 8, 39, 138, 414, 1104, 2715, 6282, 13875, 29540, 61060, 123192, 243589, 473540, 907335, 1716974, 3214066, 5959704, 10958687, 20001526, 36264579, 65359752, 117165096, 209008464, 371190217, 656540768, 1156924167, 2031676818, 3556517478]

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

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