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%I #6 Mar 17 2023 01:45:56
%S 1,18,142,1000,7388,54611,402928,2973312,21942164,161924976,
%T 1194944253,8818235182,65075230158,480230500262,3543918833192,
%U 26152776005975,192997561438126,1424248757071714,10510415297046298,77562875984896828
%N Number of n X 3 0..1 arrays with every element equal to 1, 2, 3, 4, 5, 6 or 8 king-move adjacent elements, with upper left element zero.
%C Column 3 of A299839.
%H R. H. Hardin, <a href="/A299834/b299834.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 7*a(n-1) +2*a(n-2) +7*a(n-3) -6*a(n-4) -15*a(n-5) +a(n-6) +2*a(n-7) -5*a(n-8) -2*a(n-9) for n>10.
%e Some solutions for n=5
%e ..0..0..0. .0..0..1. .0..0..0. .0..1..0. .0..0..0. .0..0..0. .0..0..0
%e ..1..1..0. .0..0..1. .1..0..1. .0..0..1. .1..0..1. .1..0..1. .0..1..0
%e ..1..1..1. .0..1..0. .0..1..1. .0..0..0. .1..1..1. .0..1..0. .0..1..0
%e ..1..0..0. .0..1..1. .1..1..0. .1..0..0. .0..0..0. .1..1..0. .0..0..0
%e ..1..1..0. .0..1..1. .0..0..0. .1..1..0. .0..1..1. .1..0..1. .1..1..0
%Y Cf. A299839.
%K nonn
%O 1,2
%A _R. H. Hardin_, Feb 20 2018
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