Number of distinct prime divisors of prime(n)*prime(n-1) - 1.

Terms

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