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Search: id:A107745
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A107745 Smallest prime factor of 6*n-1. +0
6
5, 11, 17, 23, 29, 5, 41, 47, 53, 59, 5, 71, 7, 83, 89, 5, 101, 107, 113, 7, 5, 131, 137, 11, 149, 5, 7, 167, 173, 179, 5, 191, 197, 7, 11, 5, 13, 227, 233, 239, 5, 251, 257, 263, 269, 5, 281, 7, 293, 13, 5, 311, 317, 17, 7, 5, 11, 347, 353, 359, 5, 7, 13, 383, 389, 5, 401, 11 (list; graph; listen)
OFFSET

1,1

COMMENT

If 6*n-1 is prime, a(n) = 6*n-1. Cf. A107744 Smallest prime factor of 6*n+1, A107746 Values of n such that A107745(n)>A107746(n), A107747 Values of n such that A107745(n)<A107746(n).

FORMULA

a(n) = A020639(6n-1). - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jan 23 2007

MATHEMATICA

A107745[n_]:= FactorInteger[6 n - 1][[1, 1]]

CROSSREFS

Cf. A107744, A107746, A107747.

Cf. A111863.

Sequence in context: A032646 A123083 A157847 this_sequence A111863 A043389 A000966

Adjacent sequences: A107742 A107743 A107744 this_sequence A107746 A107747 A107748

KEYWORD

nonn

AUTHOR

Zak Seidov (zakseidov(AT)yahoo.com), May 23 2005

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Last modified December 8 08:31 EST 2009. Contains 170430 sequences.


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