Rotatable partitions.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =2a(5) =2a(6) =4a(7) =6a(8) =6a(9) =8a(10) =11a(11) =13a(12) =17a(13) =24a(14) =28a(15) =36a(16) =47a(17) =56a(18) =69a(19) =94a(20) =114a(21) =138a(22) =177a(23) =218a(24) =262a(25) =333a(26) =410a(27) =496a(28) =615a(29) =755