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Number of 3Xn 0..2 arrays x(i,j) with each element horizontally or antidiagonally next to at least one element with value (x(i,j)+1) mod 3, and upper left element zero
1

%I #4 Oct 25 2013 13:03:14

%S 0,0,0,30,260,2358,20430,176774,1527918,13204026,114099558,985963206,

%T 8519922122,73622499446,636187953758,5497437822074,47504550336526,

%U 410497104019406,3547194348471034,30652074338152030,264871210587660230

%N Number of 3Xn 0..2 arrays x(i,j) with each element horizontally or antidiagonally next to at least one element with value (x(i,j)+1) mod 3, and upper left element zero

%C Row 3 of A230614

%H R. H. Hardin, <a href="/A230615/b230615.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 15*a(n-1) -64*a(n-2) +61*a(n-3) +181*a(n-4) -210*a(n-5) -679*a(n-6) +577*a(n-7) +2166*a(n-8) -2571*a(n-9) -789*a(n-10) +760*a(n-11) +618*a(n-12) +264*a(n-13) +56*a(n-14) for n>17

%e Some solutions for n=4

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

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

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

%K nonn

%O 1,4

%A _R. H. Hardin_, Oct 25 2013