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A184370 1/3 the number of (n+1)X4 0..2 arrays with every 2X2 subblock having at least two equal elements connected horizontally or vertically.

%I A184370 #7 Jul 22 2025 09:31:37
%S A184370 1107,49235,2167173,95528423,4210059673,185547841629,8177524177277,
%T A184370 360402692568245,15883791500540967,700035935394350709,
%U A184370 30852225032929689819,1359729896274471875219,59926484677950059719491
%N A184370 1/3 the number of (n+1)X4 0..2 arrays with every 2X2 subblock having at least two equal elements connected horizontally or vertically.
%C A184370 Column 3 of A184376
%H A184370 R. H. Hardin, <a href="/A184370/b184370.txt">Table of n, a(n) for n = 1..200</a>
%F A184370 Empirical: a(n)=38*a(n-1)+302*a(n-2)-1368*a(n-3)-6770*a(n-4)+12666*a(n-5)-575*a(n-6)-5790*a(n-7)+828*a(n-8)+648*a(n-9)
%e A184370 Some solutions for 3X4 with a(1,1)=0
%e A184370 ..0..0..0..2....0..1..1..1....0..1..0..1....0..0..2..1....0..1..1..1
%e A184370 ..1..2..2..2....0..1..1..0....0..1..0..1....1..0..2..1....2..1..2..0
%e A184370 ..0..2..2..0....2..2..2..2....1..1..0..0....1..1..2..1....0..0..0..0
%K A184370 nonn
%O A184370 1,1
%A A184370 _R. H. Hardin_ Jan 12 2011