79989880domain: NAppears in sequencesa(0)=1, a(n) = M(n) + Sum_{k=1..n-1} M(k)*a(n-k-1), where M(n) are the Motzkin numbers (A001006).at n=19A045994Number of dispersed Dyck paths of length n having no ascents of length 1.at n=39A191385