Number of subsets of {1..n} such that no two elements have the same sorted prime signature.

Terms

a(0) =1a(1) =2a(2) =4a(3) =6a(4) =12a(5) =16a(6) =32a(7) =40a(8) =80a(9) =120a(10) =180a(11) =216a(12) =432a(13) =504a(14) =672a(15) =840a(16) =1680a(17) =1920a(18) =2880a(19) =3240a(20) =4320a(21) =5184a(22) =6048a(23) =6720a(24) =13440a(25) =17920a(26) =20480a(27) =30720a(28) =38400a(29) =42240