204928domain: NAppears in sequencesa(n) = Sum_{p in P} y(1)*y(2), where P is the set of partitions of n, and y(k) is the number of parts with multiplicity at least k in p.at n=37A316861a(n) = Sum_{k=0..floor(n/3)} 2^(n-2*k) * binomial(k,n-3*k)^2.at n=21A387485