cp's OEIS Frontend

A184556 Number of (n+1) X 2 0..2 arrays with no 2 X 2 subblock summing to less than 4.

%I A184556 #9 Feb 27 2018 10:38:26
%S A184556 50,336,2167,14180,92429,603249,3935721,25680486,167558680,1093290051,
%T A184556 7133495992,46544663377,303694712145,1981548052649,12929209539882,
%U A184556 84360538526896,550435849841567,3591485193655532,23433731463177813
%N A184556 Number of (n+1) X 2 0..2 arrays with no 2 X 2 subblock summing to less than 4.
%C A184556 Column 1 of A184564.
%H A184556 R. H. Hardin, <a href="/A184556/b184556.txt">Table of n, a(n) for n = 1..200</a>
%F A184556 Empirical: a(n) = 6*a(n-1) + 7*a(n-2) - 23*a(n-3) - 4*a(n-4) + 12*a(n-5).
%F A184556 Empirical g.f.: x*(50 + 36*x - 199*x^2 - 24*x^3 + 108*x^4) / ((1 + 2*x)*(1 - 8*x + 9*x^2 + 5*x^3 - 6*x^4)). - _Colin Barker_, Feb 27 2018
%e A184556 Some solutions for 3 X 2:
%e A184556 ..2..1....1..2....0..0....1..2....0..2....1..0....2..0....2..0....2..0....2..2
%e A184556 ..2..1....2..0....2..2....1..1....2..1....2..2....1..1....1..2....1..2....2..1
%e A184556 ..1..0....2..0....0..0....2..2....0..2....0..2....2..1....0..1....2..2....1..0
%Y A184556 Cf. A184564.
%K A184556 nonn
%O A184556 1,1
%A A184556 _R. H. Hardin_, Jan 17 2011