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 A220687 Number of ways to reciprocally link elements of an nX7 array either to themselves or to exactly two horizontal, vertical or antidiagonal neighbors 1

%I #4 Dec 17 2012 19:24:36

%S 1,1081,362057,128995678,42362190063,14108684022136,4701615485821782,

%T 1566852499542855296,522108399243273023731,173978947909208417520148,

%U 57974051497341052095013087,19318375776055542860988503113

%N Number of ways to reciprocally link elements of an nX7 array either to themselves or to exactly two horizontal, vertical or antidiagonal neighbors

%C Column 7 of A220688

%H R. H. Hardin, <a href="/A220687/b220687.txt">Table of n, a(n) for n = 1..114</a>

%e Some solutions for n=3 0=self 2=n 3=ne 4=w 6=e 7=sw 8=s (reciprocal directions total 10)

%e .00.00.67.46.46.47.00...00.00.00.00.68.48.00...00.00.68.48.68.46.48

%e .00.36.46.47.37.67.47...00.67.48.00.27.26.47...00.78.28.28.26.47.28

%e .00.00.36.34.36.34.00...36.46.24.36.46.34.00...36.24.26.24.36.46.24

%K nonn

%O 1,2

%A _R. H. Hardin_ Dec 17 2012

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Last modified June 17 10:50 EDT 2024. Contains 373445 sequences. (Running on oeis4.)