A167746 Number of prime divisors of A001222 (counted with multiplicity), with a(1) = 1 by convention.

1, 0, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 2, 0, 1, 0, 1, 1, 1, 0, 2, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 2, 0, 1, 1, 2, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 2, 1, 2, 1, 1, 0, 2, 0, 1, 1, 2, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1, 2, 1, 0, 2, 1, 1, 1, 2, 0, 2, 1, 1, 1, 1, 1, 2, 0, 1, 1, 2, 0, 1, 0, 2, 1

Offset

1,16

Comments

First 31 terms the same as A050370.

Links

Antti Karttunen, Table of n, a(n) for n = 1..10000

Index entries for sequences computed from exponents in factorization of n

Formula

a(1) = 1; for n > 1, a(n) = A001222(A001222(n)). - Antti Karttunen, Jul 28 2017

Mathematica

Array[If[# == 1, 1, Nest[PrimeOmega, #, 2]] &, 105] (* Michael De Vlieger, Jul 29 2017 *)

Prog

(Scheme) (define (A167746 n) (if (= 1 n) 1 (A001222 (A001222 n)))) ;; Antti Karttunen, Jul 28 2017
(PARI) a(n) = if (n==1, 1, bigomega(bigomega(n))); \\ Michel Marcus, Jul 28 2017

Crossrefs

Cf. A001222.

Sequence in context: A052344 A339375 A147768 * A360616 A050370 A050374

Adjacent sequences: A167743 A167744 A167745 * A167747 A167748 A167749

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, Nov 10 2009

Extensions

Name clarified by Antti Karttunen, Jul 28 2017

Status

approved