Number of distinct primes dividing p-1, where p = n-th prime.

Terms

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