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A167746 Number of prime divisors of A001222 (counted with multiplicity), with a(1) = 1 by convention. 3
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 (list; graph; refs; listen; history; text; internal format)
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: A090465 A052344 A147768 * A050370 A050374 A238877

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

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Last modified April 9 15:09 EDT 2020. Contains 333355 sequences. (Running on oeis4.)