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A262414 Number of (n+1) X (2+1) 0..1 arrays with each row divisible by 3 and column not divisible by 3, read as a binary number with top and left being the most significant bits.

%I A262414 #8 Dec 31 2018 11:27:51
%S A262414 0,4,12,48,144,468,1404,4320,12960,39204,117612,353808,1061424,
%T A262414 3187188,9561564,28693440,86080320,258267204,774801612,2324483568,
%U A262414 6973450704,20920588308,62761764924,188286003360,564858010080,1694576156004
%N A262414 Number of (n+1) X (2+1) 0..1 arrays with each row divisible by 3 and column not divisible by 3, read as a binary number with top and left being the most significant bits.
%H A262414 R. H. Hardin, <a href="/A262414/b262414.txt">Table of n, a(n) for n = 1..210</a>
%F A262414 Empirical: a(n) = 3*a(n-1) + 3*a(n-2) - 9*a(n-3).
%F A262414 Empirical g.f.: 4*x^2 / ((1 - 3*x)*(1 - 3*x^2)). - _Colin Barker_, Dec 31 2018
%e A262414 Some solutions for n=4:
%e A262414 ..1..1..0....0..1..1....0..1..1....1..1..0....0..1..1....1..1..0....0..0..0
%e A262414 ..0..1..1....1..1..0....0..1..1....0..1..1....1..1..0....0..1..1....1..1..0
%e A262414 ..0..1..1....1..1..0....0..1..1....0..0..0....0..0..0....1..1..0....0..0..0
%e A262414 ..0..0..0....1..1..0....1..1..0....0..0..0....1..1..0....0..0..0....1..1..0
%e A262414 ..0..1..1....0..1..1....0..1..1....1..1..0....0..0..0....0..0..0....0..1..1
%Y A262414 Column 2 of A262420.
%K A262414 nonn
%O A262414 1,2
%A A262414 _R. H. Hardin_, Sep 22 2015