cp's OEIS Frontend

A206231 Number of (n+1) X 2 0..3 arrays with every 2 X 3 or 3 X 2 subblock having exactly two equal edges, and new values 0..3 introduced in row major order.

%I A206231 #8 Jun 14 2018 09:32:37
%S A206231 15,60,310,1640,8910,51066,294546,1710184,10051522,59273370,350336326,
%T A206231 2076929912,12328636710,73241168202,435453806538,2590088923960,
%U A206231 15409982499130,91703551575882,545793722630878,3248685323916392
%N A206231 Number of (n+1) X 2 0..3 arrays with every 2 X 3 or 3 X 2 subblock having exactly two equal edges, and new values 0..3 introduced in row major order.
%C A206231 Column 1 of A206238.
%H A206231 R. H. Hardin, <a href="/A206231/b206231.txt">Table of n, a(n) for n = 1..210</a>
%F A206231 Empirical: a(n) = 8*a(n-1) -11*a(n-2) +36*a(n-3) -303*a(n-4) +232*a(n-5) +147*a(n-6) +756*a(n-7) for n>8.
%F A206231 Empirical g.f.: x*(15 - 60*x - 5*x^2 - 720*x^3 + 1585*x^4 + 1366*x^5 + 2793*x^6 - 378*x^7) / ((1 - 4*x)*(1 - x - x^2 - 3*x^3)*(1 - 3*x - 7*x^2 - 63*x^3)). - _Colin Barker_, Jun 14 2018
%e A206231 Some solutions for n=4:
%e A206231 ..0..1....0..0....0..1....0..0....0..0....0..1....0..1....0..0....0..0....0..0
%e A206231 ..0..0....0..1....0..0....0..1....1..0....2..1....2..0....1..1....0..1....0..1
%e A206231 ..0..1....1..2....0..1....1..0....0..1....3..1....0..0....2..1....1..2....1..2
%e A206231 ..1..2....1..1....1..0....0..0....0..0....0..1....3..0....1..0....2..2....1..1
%e A206231 ..1..1....0..1....0..0....2..2....0..2....3..3....2..1....0..0....1..1....0..0
%Y A206231 Cf. A206238.
%K A206231 nonn
%O A206231 1,1
%A A206231 _R. H. Hardin_, Feb 05 2012