Number of ordered set partitions of the multiset [a,a,1,1,...,1] with two "a" and n "1".

Terms

a(0) =1a(1) =2a(2) =7a(3) =15a(4) =33a(5) =59a(6) =111a(7) =182a(8) =307a(9) =481a(10) =757a(11) =1134a(12) =1713a(13) =2483a(14) =3611a(15) =5117a(16) =7238a(17) =10029a(18) =13888a(19) =18900a(20) =25682a(21) =34442a(22) =46057a(23) =60934a(24) =80428a(25) =105159a(26) =137137a(27) =177495a(28) =229069a(29) =293694