%I #6 Mar 15 2023 11:34:57
%S 1,10,53,272,1390,7179,37042,191135,986243,5089160,26260738,135509178,
%T 699246723,3608214131,18618905868,96076245152,495767309402,
%U 2558230969852,13200841543223,68118250289325,351500016661296,1813790888521066
%N Number of n X 3 0..1 arrays with every element equal to 1, 2 or 3 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
%C Column 3 of A300427.
%H R. H. Hardin, <a href="/A300422/b300422.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 5*a(n-1) +3*a(n-2) -11*a(n-3) +a(n-4) -11*a(n-5) -2*a(n-6) +14*a(n-7) -6*a(n-8) -8*a(n-9) -4*a(n-10) -8*a(n-11) +4*a(n-13) for n>14.
%e Some solutions for n=5
%e ..0..1..0. .0..0..0. .0..0..1. .0..0..0. .0..0..1. .0..0..0. .0..0..1
%e ..0..1..0. .1..1..0. .0..1..0. .0..1..0. .0..1..1. .1..0..0. .1..1..1
%e ..1..0..1. .1..0..0. .0..0..1. .1..0..1. .1..0..1. .1..1..0. .0..0..0
%e ..0..0..1. .1..1..1. .1..0..1. .0..1..1. .0..1..0. .0..1..0. .0..1..1
%e ..1..1..1. .1..0..0. .1..0..1. .0..0..1. .1..0..0. .0..1..1. .1..0..0
%Y Cf. A300427.
%K nonn
%O 1,2
%A _R. H. Hardin_, Mar 05 2018
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