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A318011 Number of nX3 0..1 arrays with every element unequal to 0, 1, 2 or 3 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero. 1

%I #4 Aug 12 2018 19:33:57

%S 4,28,118,508,2130,8971,37700,158613,667178,2806643,11806334,49664719,

%T 208919728,878843413,3696948061,15551606501,65419489183,275194053961,

%U 1157633112776,4869707055676,20484941672721,86172090154282

%N Number of nX3 0..1 arrays with every element unequal to 0, 1, 2 or 3 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

%C Column 3 of A318016.

%H R. H. Hardin, <a href="/A318011/b318011.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 3*a(n-1) +5*a(n-2) +3*a(n-4) -4*a(n-5) -11*a(n-6) -6*a(n-7) -a(n-8) -4*a(n-9) -4*a(n-10) -a(n-11) for n>14

%e Some solutions for n=5

%e ..0..0..1. .0..0..1. .0..1..1. .0..0..0. .0..0..0. .0..1..1. .0..0..0

%e ..0..0..1. .1..1..1. .0..1..1. .1..0..0. .1..1..0. .0..1..0. .0..0..1

%e ..0..0..1. .1..1..0. .0..0..0. .1..0..0. .1..1..1. .1..0..0. .0..1..1

%e ..0..0..1. .0..0..1. .0..0..0. .1..1..1. .1..1..1. .1..0..0. .1..1..1

%e ..1..0..1. .0..1..1. .1..0..1. .0..1..1. .0..0..0. .1..1..1. .1..1..0

%Y Cf. A318016.

%K nonn

%O 1,1

%A _R. H. Hardin_, Aug 12 2018

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Last modified April 13 01:51 EDT 2024. Contains 371639 sequences. (Running on oeis4.)