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A240515 Number of nX4 0..1 arrays with no element equal to exactly two horizontal and vertical neighbors, with new values 0..1 introduced in row major order.

%I A240515 #10 Jul 23 2025 11:02:08
%S A240515 5,10,28,99,326,1080,3765,13282,46928,166611,595402,2132856,7647821,
%T A240515 27453594,98644580,354622219,1275200926,4586567656,16499401997,
%U A240515 59359672578,213570572184,768440651027,2764982991218,9949082534056
%N A240515 Number of nX4 0..1 arrays with no element equal to exactly two horizontal and vertical neighbors, with new values 0..1 introduced in row major order.
%C A240515 Column 4 of A240519
%H A240515 R. H. Hardin, <a href="/A240515/b240515.txt">Table of n, a(n) for n = 1..210</a>
%F A240515 Empirical: a(n) = 5*a(n-1) -5*a(n-2) +4*a(n-3) -3*a(n-4) -49*a(n-5) +10*a(n-6) +15*a(n-7) +45*a(n-8) +124*a(n-9) +131*a(n-10) +301*a(n-11) +18*a(n-12) -615*a(n-13) -201*a(n-14) -1508*a(n-15) -823*a(n-16) -413*a(n-17) -254*a(n-18) +2467*a(n-19) +793*a(n-20) +4516*a(n-21) +1071*a(n-22) +2289*a(n-23) -2289*a(n-25) -1071*a(n-26) -4516*a(n-27) -793*a(n-28) -2467*a(n-29) +254*a(n-30) +413*a(n-31) +823*a(n-32) +1508*a(n-33) +201*a(n-34) +615*a(n-35) -18*a(n-36) -301*a(n-37) -131*a(n-38) -124*a(n-39) -45*a(n-40) -15*a(n-41) -10*a(n-42) +49*a(n-43) +3*a(n-44) -4*a(n-45) +5*a(n-46) -5*a(n-47) +a(n-48)
%e A240515 Some solutions for n=4
%e A240515 ..0..1..1..1....0..1..0..1....0..1..0..1....0..0..0..1....0..1..1..1
%e A240515 ..1..0..1..0....1..1..1..0....0..1..0..1....1..0..1..0....0..0..1..0
%e A240515 ..1..1..0..0....0..1..0..1....1..0..1..0....1..1..0..1....0..1..0..1
%e A240515 ..1..0..1..0....1..0..0..0....0..1..1..1....1..0..0..0....1..1..1..0
%K A240515 nonn
%O A240515 1,1
%A A240515 _R. H. Hardin_, Apr 06 2014