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%I #6 Jan 20 2024 17:46:00
%S 1,14,43,194,675,2666,9819,37382,140039,528962,1989787,7501790,
%T 28252719,106464314,401084083,1511229542,5693728487,21452605794,
%U 80826937611,304534567726,1147401249247,4323099142602,16288258059235,61369756239670
%N Number of n X 3 0..1 arrays with every element equal to 1, 2 or 3 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.
%C Column 3 of A302224.
%H R. H. Hardin, <a href="/A302219/b302219.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 3*a(n-1) +7*a(n-2) -5*a(n-3) -34*a(n-4) -46*a(n-5) +64*a(n-6) +112*a(n-7) +60*a(n-8) -96*a(n-9) -80*a(n-10) -64*a(n-11).
%e Some solutions for n=5
%e ..0..0..0. .0..0..0. .0..0..0. .0..0..0. .0..0..0. .0..0..1. .0..0..0
%e ..1..1..0. .0..1..1. .1..1..0. .1..0..1. .1..1..1. .1..1..0. .0..1..1
%e ..1..0..0. .1..0..1. .0..0..1. .1..1..0. .0..0..1. .0..1..1. .1..0..1
%e ..1..0..0. .1..0..1. .0..1..1. .0..1..0. .1..0..0. .0..0..1. .1..0..0
%e ..1..1..1. .0..1..1. .0..0..1. .1..0..0. .1..1..0. .1..1..0. .1..1..0
%Y Cf. A302224.
%K nonn
%O 1,2
%A _R. H. Hardin_, Apr 03 2018
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