A162022 - OEIS

A162022

Smallest prime factor of n-th odd composite integers A071904.

3, 3, 3, 5, 3, 3, 5, 3, 3, 7, 3, 5, 3, 3, 5, 3, 3, 7, 3, 5, 3, 7, 3, 5, 3, 3, 3, 5, 3, 7, 11, 3, 5, 3, 7, 3, 3, 11, 5, 3, 3, 5, 3, 7, 3, 13, 3, 5, 3, 3, 5, 11, 3, 3, 3, 7, 5, 3, 11, 3, 5, 7, 3, 13, 3, 3, 5, 3, 3, 5, 13, 3, 11, 3, 7, 3, 5, 3, 3, 5, 3, 3, 7, 17, 3, 5, 3, 13, 7, 3, 5, 3, 3, 11, 3, 17, 5, 3, 7, 3

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OFFSET

1,1

COMMENTS

Records are for n's such that A071904(n) = squares of primes.

a(n) = A020639(A071904(n)). [Reinhard Zumkeller, Oct 10 2011]

LINKS

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

EXAMPLE

A071904(1)=9, hence a(1)=3, A071904(4)=25, hence a(4)=5.

MATHEMATICA

nn=501; With[{ci=Complement[Range[9, nn, 2], Prime[Range[PrimePi[nn]]]]}, FactorInteger[ #][[1, 1]]&/@ci] (* Harvey P. Dale, Nov 30 2012 *)