222884domain: NAppears in sequencesLet p(n, s, x) be predicate that number of occurrences of s's in x >= 2*n - the length of the longest sequence of s's in x. Then a(n)=#{x in {0,1}* | x ends in 0 and p(n,0,x) and (there is no prefix y of x such that p(n,0,y) or p(n,1,y))}.at n=6A000530a(n) = floor(9^n/7^n).at n=49A094991