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A207781 Number of nX4 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 0 and 1 0 1 vertically.

%I A207781 #7 Jul 22 2025 20:50:21
%S A207781 9,81,257,791,2200,6418,19041,55101,160274,468839,1365913,3979457,
%T A207781 11607265,33840611,98648082,287610828,838518475,2444629303,7127128826,
%U A207781 20778544998,60578554943,176612608043,514899479923,1501152602979
%N A207781 Number of nX4 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 0 and 1 0 1 vertically.
%C A207781 Column 4 of A207785
%H A207781 R. H. Hardin, <a href="/A207781/b207781.txt">Table of n, a(n) for n = 1..210</a>
%F A207781 Empirical: a(n) = a(n-1) +16*a(n-3) +6*a(n-4) +6*a(n-5) -50*a(n-6) -40*a(n-7) -3*a(n-8) +56*a(n-9) +25*a(n-10) -10*a(n-11) -25*a(n-12) +38*a(n-13) -16*a(n-14) -19*a(n-15) +12*a(n-16) +25*a(n-17) +3*a(n-18) -10*a(n-19) -8*a(n-20) +13*a(n-21) -4*a(n-22) -11*a(n-23) +a(n-24) +5*a(n-25) -2*a(n-27) for n>31
%e A207781 Some solutions for n=4
%e A207781 ..1..1..0..0....1..0..1..0....1..1..1..1....0..1..0..0....1..1..1..1
%e A207781 ..0..1..0..1....1..0..1..0....0..1..0..1....1..1..0..0....1..1..1..1
%e A207781 ..0..0..1..0....1..1..0..1....0..1..0..0....1..1..1..1....1..1..1..1
%e A207781 ..1..0..1..0....0..1..0..0....1..0..1..0....1..1..1..1....1..1..1..0
%K A207781 nonn
%O A207781 1,1
%A A207781 _R. H. Hardin_ Feb 20 2012