%I #11 May 10 2013 12:44:47
%S 1,2,4,8,16,32,63,124,243,476,933,1830,3590,7043,13818,27110,53186,
%T 104342,204701,401588,787846,1545619,3032243,5948749,11670441,
%U 22895434,44916973,88119508,172875575,339152648,665360153,1305324126,2560825244
%N Number of (0,1)-strings of length n that avoid the substrings of substrings 11101011 and 101111.
%D I. P. Goulden and D. M. Jackson, Combinatorial Enumeration, Wiley, N.Y., 1983,(Problem 2.8.4).
%F G.f.: (1+x+x^2+x^3+x^4+2*x^5+3*x^6+3*x^7+2*x^8+x^9)/(1-x-x^2-x^3-x^4-2*x^7-2*x^8-x^9-x^10). a(n) = a(n-1)+a(n-2)+a(n-3)+a(n-4)+2*a(n-7)+2*a(n-8)+a(n-9)+a(n-10).
%F Goulden and Jackson give the g.f. in the equivalent form (1+x^5+x^6-x^8-x^9-x^10)/(1-2*x+x^5-2*x^7+x^9+x^11). - _N. J. A. Sloane_, Apr 09 2011
%Y Cf. A062257, A062258.
%K nonn
%O 0,2
%A _Vladeta Jovovic_, Jun 14 2001