cp's OEIS Frontend

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.

%I A198648 #11 May 15 2018 09:00:57
%S A198648 0,1,1,2,3,6,11,23,47,103,226,518,1200,2867,6946,17233,43385,111354,
%T A198648 289861,766767,2054605,5579891,15325432,42559486,119312586,337469019,
%U A198648 961850000,2760643085,7971239103,23140321458,67486362815,197615025815
%N 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.
%C A198648 Column 1 of A198654.
%H A198648 R. H. Hardin, <a href="/A198648/b198648.txt">Table of n, a(n) for n = 1..200</a>
%F A198648 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 A198648 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 A198648 All solutions for n=5:
%e A198648 ..0....0....0
%e A198648 ..0....0....0
%e A198648 ..0....0....1
%e A198648 ..1....0....1
%e A198648 ..1....0....1
%Y A198648 Cf. A198654.
%K A198648 nonn
%O A198648 1,4
%A A198648 _R. H. Hardin_, Oct 28 2011