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T(n,k)=Number of nXk 0..3 arrays with no element equal to exactly three horizontal or vertical neighbors, with new values 0..3 introduced in row major order
6

%I #4 Apr 16 2014 07:24:18

%S 1,2,2,5,15,5,15,178,178,15,51,2614,9918,2614,51,187,40148,587555,

%T 587555,40148,187,715,622645,35000157,134229632,35000157,622645,715,

%U 2795,9676364,2085879115,30679522712,30679522712,2085879115,9676364,2795

%N T(n,k)=Number of nXk 0..3 arrays with no element equal to exactly three horizontal or vertical neighbors, with new values 0..3 introduced in row major order

%C Table starts

%C ...1......2..........5............15................51..................187

%C ...2.....15........178..........2614.............40148...............622645

%C ...5....178.......9918........587555..........35000157...........2085879115

%C ..15...2614.....587555.....134229632.......30679522712........7012241396116

%C ..51..40148...35000157...30679522712....26891788727245....23571710809729613

%C .187.622645.2085879115.7012241396116.23571710809729613.79236581561126536192

%H R. H. Hardin, <a href="/A241119/b241119.txt">Table of n, a(n) for n = 1..84</a>

%F Empirical for column k:

%F k=1: a(n) = 7*a(n-1) -14*a(n-2) +8*a(n-3)

%F k=2: [order 8] for n>10

%F k=3: [order 20] for n>21

%F k=4: [order 74] for n>75

%e Some solutions for n=3 k=4

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

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

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

%Y Column 1 is A007581(n-1)

%Y Column 2 is A200795

%K nonn,tabl

%O 1,2

%A _R. H. Hardin_, Apr 16 2014