401392domain: NAppears in sequencesTriangle read by rows: T(n,k) is the number of ternary sequences of length n containing k subsequences 000 (consecutively; n,k>=0).at n=57A119825Number of ternary words of length n with no 000's.at n=12A119826G.f.: Sum_{n>=0} ( (1+x)^n - 1 )^n * 2^n / (3 - 2*(1+x)^n)^(n+1).at n=5A317662