A181239 - OEIS

%I #6 Mar 26 2018 14:25:25

%S 16,178,2066,23858,275690,3185462,36806846,425288998,4914052362,

%T 56780001474,656071271338,7580653428086,87591560417790,

%U 1012087088416198,11694280472399626,135122952690874754,1561294205914890890

%N Number of n X 4 binary matrices with no 2 X 2 circuit having pattern 0101 in any orientation.

%C Column 4 of A181245.

%H R. H. Hardin, <a href="/A181239/b181239.txt">Table of n, a(n) for n=1..200</a>

%F Empirical: a(n) = 10*a(n-1) + 20*a(n-2) - 21*a(n-3) - 30*a(n-4) + 8*a(n-5).

%F Empirical g.f.: 2*x*(8 + 9*x - 17*x^2 - 13*x^3 + 4*x^4) / (1 - 10*x - 20*x^2 + 21*x^3 + 30*x^4 - 8*x^5). - _Colin Barker_, Mar 26 2018

%Y Cf. A181245.

%K nonn

%O 1,1

%A _R. H. Hardin_, Oct 10 2010