G.f.: 1/Product_{k>0} (1-x^k)^A000669(k+1).

Terms

a(0) =1a(1) =1a(2) =3a(3) =8a(4) =23a(5) =66a(6) =199a(7) =601a(8) =1861a(9) =5815a(10) =18396a(11) =58684a(12) =188764a(13) =611103a(14) =1990361a(15) =6515786a(16) =21429510a(17) =70767468a(18) =234565319a(19) =780086526a(20) =2602209961a(21) =8704547698a(22) =29191435328a(23) =98125474137a(24) =330558122499