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A183339 Number of nX7 binary arrays with each 1 adjacent to exactly one 1 vertically and one 1 horizontally.

%I A183339 #7 Jul 22 2025 08:49:53
%S A183339 1,13,37,97,407,1397,4531,16029,55471,188735,651517,2246015,7712899,
%T A183339 26544813,91374201,314289321,1081352347,3720918175,12801778315,
%U A183339 44045879629,151549077973,521423489151,1794025850189,6172623965117
%N A183339 Number of nX7 binary arrays with each 1 adjacent to exactly one 1 vertically and one 1 horizontally.
%C A183339 Equivalent to all 1s connected only in 2X2 blocks
%C A183339 Column 7 of A183342
%H A183339 R. H. Hardin, <a href="/A183339/b183339.txt">Table of n, a(n) for n = 1..200</a>
%F A183339 Empirical: a(n)=a(n-1)+2*a(n-2)+18*a(n-3)+17*a(n-4)+7*a(n-5)-40*a(n-6)-78*a(n-7)-21*a(n-8)+88*a(n-9)+62*a(n-10)-49*a(n-11)-24*a(n-12)+9*a(n-13)-18*a(n-14)+2*a(n-15)+9*a(n-16)+4*a(n-17)+4*a(n-18)
%e A183339 Some solutions for 5X7
%e A183339 ..0..0..0..1..1..0..0....1..1..0..0..0..0..0....0..0..0..0..1..1..0
%e A183339 ..0..0..0..1..1..0..0....1..1..0..0..1..1..0....1..1..0..0..1..1..0
%e A183339 ..0..0..0..0..0..1..1....0..0..0..0..1..1..0....1..1..0..0..0..0..0
%e A183339 ..1..1..0..0..0..1..1....0..0..0..0..0..0..0....0..0..1..1..0..0..0
%e A183339 ..1..1..0..0..0..0..0....0..0..0..0..0..0..0....0..0..1..1..0..0..0
%K A183339 nonn
%O A183339 1,2
%A A183339 _R. H. Hardin_ Jan 04 2011