Number of multisets of nonempty multisets of nonempty sets of positive integers with total sum n.

Terms

a(0) =1a(1) =1a(2) =3a(3) =7a(4) =17a(5) =37a(6) =87a(7) =187a(8) =414a(9) =887a(10) =1903a(11) =4008a(12) =8437a(13) =17519a(14) =36255a(15) =74384a(16) =151898a(17) =308129a(18) =622269a(19) =1249768a(20) =2499392a(21) =4975421a(22) =9865122a(23) =19481300a(24) =38331536a(25) =75149380a(26) =146840801a(27) =285990797a(28) =555297342a(29) =1074996017