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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.

A220643 Number of ways to reciprocally link elements of an n X 7 array either to themselves or to exactly one king-move neighbor.

Table of values

n a(n)
0 1
1 21
2 13152
3 3725843
4 1299348473
5 431408410784
6 145000880411157
7 48590896359378961
8 16295162098717276928
9 5463664833842177843423
10 1832013557267266441097285
11 614283122531442244792501056
12 205972692517470174457341794041
13 69063792561944299889152684046621

List of values

[1, 21, 13152, 3725843, 1299348473, 431408410784, 145000880411157, 48590896359378961, 16295162098717276928, 5463664833842177843423, 1832013557267266441097285, 614283122531442244792501056, 205972692517470174457341794041, 69063792561944299889152684046621]

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

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