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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.

A220630 Number of ways to reciprocally link elements of an nX6 array either to themselves or to exactly two horizontal or antidiagonal neighbors.

Table of values

n a(n)
1 1
2 16
3 158
4 1665
5 17527
6 183961
7 1932695
8 20301254
9 213251377
10 2240062837
11 23530357757
12 247170637157
13 2596361852466
14 27273040848960
15 286485012144200
16 3009333012881404
17 31611026051882958
18 332052638832405598

List of values

[1, 16, 158, 1665, 17527, 183961, 1932695, 20301254, 213251377, 2240062837, 23530357757, 247170637157, 2596361852466, 27273040848960, 286485012144200, 3009333012881404, 31611026051882958, 332052638832405598]

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

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