Number of rotatable partitions of [n].

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =2a(6) =3a(7) =3a(8) =5a(9) =6a(10) =8a(11) =9a(12) =11a(13) =14a(14) =19a(15) =22a(16) =28a(17) =34a(18) =44a(19) =52a(20) =63a(21) =78a(22) =99a(23) =119a(24) =144a(25) =178a(26) =219a(27) =265