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A207271 Number of 4Xn 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 1 1 and 1 0 1 vertically.

%I A207271 #7 Jul 22 2025 20:13:55
%S A207271 9,81,193,611,1602,3513,8327,17568,36988,76723,153865,308777,608391,
%T A207271 1189918,2313136,4458599,8562580,16354499,31118601,59018399,111556847,
%U A207271 210352934,395641010,742567333,1391072247,2601239676,4856734666
%N A207271 Number of 4Xn 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 1 1 and 1 0 1 vertically.
%C A207271 Row 4 of A207269
%H A207271 R. H. Hardin, <a href="/A207271/b207271.txt">Table of n, a(n) for n = 1..210</a>
%F A207271 Empirical: a(n) = 2*a(n-1) +5*a(n-2) -a(n-3) -30*a(n-4) -13*a(n-5) +54*a(n-6) +109*a(n-7) -36*a(n-8) -191*a(n-9) -186*a(n-10) +146*a(n-11) +313*a(n-12) +245*a(n-13) -177*a(n-14) -350*a(n-15) -329*a(n-16) +108*a(n-17) +320*a(n-18) +341*a(n-19) -41*a(n-20) -205*a(n-21) -228*a(n-22) -5*a(n-23) +70*a(n-24) +106*a(n-25) +23*a(n-26) -9*a(n-27) -38*a(n-28) -12*a(n-29) +9*a(n-31) +2*a(n-32) -a(n-34)
%e A207271 Some solutions for n=4
%e A207271 ..1..0..1..0....1..1..0..0....0..0..1..0....1..0..0..1....1..0..0..1
%e A207271 ..0..0..1..0....1..0..1..0....1..1..1..0....0..1..0..0....0..0..1..0
%e A207271 ..0..1..0..0....1..0..0..1....0..0..1..0....0..0..1..0....0..1..0..0
%e A207271 ..1..0..0..1....1..1..0..0....0..0..1..0....1..0..0..1....1..0..0..1
%K A207271 nonn
%O A207271 1,1
%A A207271 _R. H. Hardin_ Feb 16 2012