|
%I #9 Jun 17 2018 05:52:33
%S 15,186,2786,43804,697369,11136544,177977851,2844864002,45475406828,
%T 726936444140,11620303055791,185754246374086,2969341279822087,
%U 47465875753570892,758757303430379258,12128979771310068836
%N Number of (n+1) X 2 0..3 arrays with every 2 X 3 or 3 X 2 subblock having no more than four equal edges, and new values 0..3 introduced in row major order.
%C Column 1 of A206521.
%H R. H. Hardin, <a href="/A206514/b206514.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 18*a(n-1) - 27*a(n-2) - 76*a(n-3) - 111*a(n-4) - 66*a(n-5) - 24*a(n-6) for n>7.
%F Empirical g.f.: x*(15 - 84*x - 157*x^2 - 182*x^3 - 80*x^4 - 18*x^5 + 8*x^6) / ((1 - 3*x - 3*x^2 - 2*x^3)*(1 - 15*x - 15*x^2 - 12*x^3)). - _Colin Barker_, Jun 17 2018
%e Some solutions for n=4:
%e ..0..1....0..0....0..1....0..0....0..0....0..0....0..0....0..0....0..1....0..0
%e ..1..0....0..0....1..0....1..0....0..1....0..1....0..0....0..0....2..2....1..0
%e ..2..1....0..1....0..0....0..1....1..2....2..0....1..1....1..2....1..0....0..1
%e ..1..1....0..1....0..1....1..0....0..1....0..1....2..0....1..3....0..3....1..0
%e ..0..3....1..2....0..0....0..0....0..0....3..0....2..2....0..0....0..0....0..1
%Y Cf. A206521.
%K nonn
%O 1,1
%A _R. H. Hardin_, Feb 08 2012
| 