%I #4 Mar 31 2018 16:00:26
%S 4,13,33,70,154,433,1166,3153,8468,22750,61199,165177,445570,1201785,
%T 3241825,8746118,23596920,63667249,171782178,463490985,1250567970,
%U 3374237398,9104258583,24564843989,66280181642,178835414969,482529064189
%N Number of 3Xn 0..1 arrays with every element equal to 0, 1, 3 or 4 horizontally or antidiagonally adjacent elements, with upper left element zero.
%C Row 3 of A302081.
%H R. H. Hardin, <a href="/A302082/b302082.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 3*a(n-1) -a(n-3) -2*a(n-4) -3*a(n-5) +5*a(n-6) -18*a(n-7) -a(n-8) +13*a(n-9) +18*a(n-10) -9*a(n-11) -13*a(n-12) +38*a(n-13) +13*a(n-14) -9*a(n-15) -18*a(n-16) +13*a(n-17) +a(n-18) -18*a(n-19) -5*a(n-20) -3*a(n-21) +2*a(n-22) -a(n-23) +3*a(n-25) +a(n-26) for n>27
%e Some solutions for n=5
%e ..0..0..1..0..0. .0..1..1..0..1. .0..0..1..0..1. .0..0..1..0..1
%e ..1..0..1..1..1. .0..0..1..0..1. .1..1..1..0..0. .1..1..1..0..1
%e ..1..0..1..0..1. .1..0..1..1..1. .1..0..1..1..0. .0..0..1..1..1
%Y Cf. A302081.
%K nonn
%O 1,1
%A _R. H. Hardin_, Mar 31 2018
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