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A066727 Least factor of n^Phi(n) -1. 1
0, 1, 2, 3, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 7, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 17, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 13, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 7, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

n^Phi(n)-1 is never prime. This sequence is an outgrowth of Euler's generalization to Fermat's little theorem.

LINKS

Table of n, a(n) for n=1..100.

MATHEMATICA

a = {}; Do[ a = Append[a, FactorInteger[ n^EulerPhi[n] - 1, FactorComplete -> False][[1, 1]]], {n, 1, 100}]; a

CROSSREFS

Cf. A066699.

Sequence in context: A093476 A262597 A217607 * A076606 A056927 A094290

Adjacent sequences:  A066724 A066725 A066726 * A066728 A066729 A066730

KEYWORD

nonn

AUTHOR

Robert G. Wilson v, Jan 15 2002

STATUS

approved

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Last modified July 17 16:38 EDT 2019. Contains 325107 sequences. (Running on oeis4.)