a(n) is the number of prime divisors (counted by multiplicity) of A024675(n).

Terms

a(0) =2a(1) =2a(2) =2a(3) =3a(4) =2a(5) =3a(6) =2a(7) =2a(8) =3a(9) =2a(10) =2a(11) =3a(12) =3a(13) =3a(14) =4a(15) =4a(16) =6a(17) =2a(18) =5a(19) =3a(20) =4a(21) =2a(22) =2a(23) =3a(24) =3a(25) =3a(26) =5a(27) =2a(28) =5a(29) =2