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 A198648 Number of n X 1 0..6 arrays with values 0..6 introduced in row major order and each element equal to at least one horizontal or vertical neighbor. 1

%I

%S 0,1,1,2,3,6,11,23,47,103,226,518,1200,2867,6946,17233,43385,111354,

%T 289861,766767,2054605,5579891,15325432,42559486,119312586,337469019,

%U 961850000,2760643085,7971239103,23140321458,67486362815,197615025815

%N Number of n X 1 0..6 arrays with values 0..6 introduced in row major order and each element equal to at least one horizontal or vertical neighbor.

%C Column 1 of A198654.

%H R. H. Hardin, <a href="/A198648/b198648.txt">Table of n, a(n) for n = 1..200</a>

%F Empirical: a(n) = 6*a(n-1) +a(n-2) -60*a(n-3) +50*a(n-4) +226*a(n-5) -231*a(n-6) -416*a(n-7) +361*a(n-8) +388*a(n-9) -180*a(n-10) -144*a(n-11) for n>12.

%F Empirical g.f.: x^2*(1 - 5*x - 5*x^2 + 50*x^3 - 4*x^4 - 184*x^5 + 36*x^6 + 303*x^7 - 3*x^8 - 189*x^9 - 53*x^10) / ((1 - x)*(1 + x)*(1 - 2*x)*(1 + 2*x)*(1 - 3*x)*(1 - x - x^2)*(1 - x - 3*x^2)*(1 - x - 4*x^2)). - _Colin Barker_, May 15 2018

%e All solutions for n=5:

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

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

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

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

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

%Y Cf. A198654.

%K nonn

%O 1,4

%A _R. H. Hardin_, Oct 28 2011

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Last modified March 25 00:50 EDT 2023. Contains 361511 sequences. (Running on oeis4.)