Triangle read by rows: T(n,k) (n,k>=0) = number of peakless Motzkin paths of length n having k valleys (i.e., (1,-1) followed by (1,1)) at level zero (can be easily translated into RNA secondary structure terminology).

A110333

Triangle read by rows: T(n,k) (n,k>=0) = number of peakless Motzkin paths of length n having k valleys (i.e., (1,-1) followed by (1,1)) at level zero (can be easily translated into RNA secondary structure terminology).