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A078313 Number of distinct prime factors of n*rad(n)+1, where rad=A007947 (squarefree kernel). 6
1, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 3, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 2, 3, 1, 2, 2, 2, 2, 3, 2, 3, 2, 2, 2, 3, 2, 2, 1, 2, 2, 3, 3, 2, 2, 4, 1, 2, 2, 2, 3, 3, 2, 3, 2, 3, 2, 2, 1, 2, 2, 2, 2, 2, 1, 3, 2, 2, 2, 2, 1, 4, 1, 2, 2, 3, 2, 2, 2, 2, 2, 4, 1, 2, 2, 3, 2, 3, 2, 3, 3, 3, 1, 2, 1, 3, 1, 3, 3, 2, 2, 3, 2, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

a(n)=A001221(A078310(n)).

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

MATHEMATICA

A078313[n_] := PrimeNu[n*Times @@ FactorInteger[n][[All, 1]] + 1]; Array[A078313, 50] (* G. C. Greubel, Apr 25 2017 *)

PROG

(PARI) a(n)=omega(n*vecprod(factor(n)[, 1])+1) \\ Charles R Greathouse IV, Jul 09 2013

(Haskell)

a078313 = a001221 . a078310  -- Reinhard Zumkeller, Jul 23 2013

CROSSREFS

Cf. A078314, A078315.

Sequence in context: A184221 A226898 A033111 * A025827 A025826 A161235

Adjacent sequences:  A078310 A078311 A078312 * A078314 A078315 A078316

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Nov 23 2002

STATUS

approved

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Last modified October 15 00:14 EDT 2019. Contains 328025 sequences. (Running on oeis4.)