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 A231051 Number of 3Xn 0..3 arrays x(i,j) with each element horizontally, diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 4 and at least one element with value (x(i,j)-1) mod 4, no adjacent elements equal, and upper left element zero 1

%I #4 Nov 03 2013 07:17:57

%S 0,2,50,128,644,5100,33696,211032,1354848,8755256,56382600,362808600,

%T 2335743720,15038803080,96821412760,623339871560,4013124023592,

%U 25836921761608,166340644854200,1070917308473608,6894671429298216

%N Number of 3Xn 0..3 arrays x(i,j) with each element horizontally, diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 4 and at least one element with value (x(i,j)-1) mod 4, no adjacent elements equal, and upper left element zero

%C Row 3 of A231049

%H R. H. Hardin, <a href="/A231051/b231051.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 6*a(n-1) +18*a(n-3) +17*a(n-4) -98*a(n-5) -32*a(n-6) +6*a(n-7) -16*a(n-8) +36*a(n-9) -8*a(n-10) for n>11

%e Some solutions for n=4

%e ..0..3..0..3....0..3..2..3....0..3..2..3....0..1..0..1....0..1..2..3

%e ..2..1..2..1....2..1..0..3....2..1..0..1....0..3..2..1....2..3..0..3

%e ..2..3..0..1....0..3..2..3....0..3..2..1....0..1..0..3....0..1..2..3

%K nonn

%O 1,2

%A _R. H. Hardin_, Nov 03 2013

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Last modified November 29 09:17 EST 2023. Contains 367429 sequences. (Running on oeis4.)