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Number of ways to reciprocally link elements of an 7Xn array either to themselves or to exactly one horizontal or antidiagonal neighbor
1

%I #4 Dec 16 2012 05:57:00

%S 1,610,27716,3128843,252139015,22926570957,1996515036228,

%T 176531479976571,15526120567015962,1368042952494285120,

%U 120466174602717968172,10610162775514570773634,934433508779628038701082

%N Number of ways to reciprocally link elements of an 7Xn array either to themselves or to exactly one horizontal or antidiagonal neighbor

%C Row 7 of A220562

%H R. H. Hardin, <a href="/A220568/b220568.txt">Table of n, a(n) for n = 1..210</a>

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

%e ..0..7..7....0..0..0....6..4..0....0..0..0....0..7..0....6..4..0....6..4..0

%e ..3..3..7....0..7..0....6..4..0....0..6..4....3..6..4....0..7..0....0..0..7

%e ..0..3..0....3..6..4....0..6..4....0..6..4....0..7..0....3..6..4....0..3..0

%e ..6..4..0....0..7..0....0..0..7....0..6..4....3..6..4....0..6..4....0..6..4

%e ..6..4..7....3..6..4....0..3..0....6..4..0....0..0..0....0..0..0....0..7..0

%e ..0..3..7....6..4..0....0..0..0....6..4..7....0..7..7....6..4..0....3..6..4

%e ..0..3..0....0..0..0....0..0..0....0..3..0....3..3..0....0..0..0....6..4..0

%K nonn

%O 1,2

%A _R. H. Hardin_ Dec 16 2012