cp's OEIS Frontend

A207069 Number of 2 X n 0..1 arrays avoiding 0 0 1 and 0 1 0 horizontally and 0 0 1 and 1 0 1 vertically.

%I A207069 #14 Feb 17 2018 20:29:33
%S A207069 4,16,36,81,196,441,961,2116,4624,10000,21609,46656,100489,216225,
%T A207069 465124,1000000,2149156,4618201,9922500,21316689,45792289,98366724,
%U A207069 211295296,453860416,974875729,2093977600,4497714225,9660727521,20750402500
%N A207069 Number of 2 X n 0..1 arrays avoiding 0 0 1 and 0 1 0 horizontally and 0 0 1 and 1 0 1 vertically.
%C A207069 Row 2 of A207068.
%H A207069 R. H. Hardin, <a href="/A207069/b207069.txt">Table of n, a(n) for n = 1..210</a>
%F A207069 Empirical: a(n) = 3*a(n-1) - 2*a(n-2) + 3*a(n-3) - 6*a(n-4) + 3*a(n-7) + a(n-8) - a(n-10).
%F A207069 Empirical g.f.: x*(4 + 4*x - 4*x^2 - 7*x^3 + x^4 + 3*x^5 + 3*x^6 + x^7 - x^8 - x^9) / ((1 - x)*(1 + x^2 - x^3)*(1 - x - x^3)*(1 - x - 2*x^2 - x^3)). - _Colin Barker_, Feb 17 2018
%e A207069 Some solutions for n=4:
%e A207069   1 0 1 1     0 1 1 1     1 0 0 0     0 1 1 0     0 1 1 0
%e A207069   1 0 1 1     1 1 0 1     0 0 0 0     0 1 1 0     0 0 0 0
%K A207069 nonn
%O A207069 1,1
%A A207069 _R. H. Hardin_, Feb 14 2012