a(n) = tau(n)-1 if n is odd or tau(n)-2 if n is even.

Terms

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