Number of sets of nonempty integer partitions with a total of n parts and total sum of 2n.

Terms

a(0) =1a(1) =1a(2) =3a(3) =10a(4) =30a(5) =94a(6) =287a(7) =854a(8) =2501a(9) =7222a(10) =20502a(11) =57412a(12) =158678a(13) =433204a(14) =1169274a(15) =3122747a(16) =8256669a(17) =21627238a(18) =56150750a(19) =144570308a(20) =369288160a(21) =936246670a(22) =2356750215a(23) =5892267672a(24) =14636329019a(25) =36131588682a(26) =88667056302a(27) =216353770900a(28) =525040244748