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A015848 Numbers n such that phi(n + 7) | sigma(n) for n not congruent to 0 (mod 3). 0
11, 14, 23, 35, 59, 71, 77, 107, 110, 119, 131, 140, 158, 161, 167, 179, 203, 239, 251, 253, 280, 287, 290, 304, 311, 329, 347, 359, 371, 383, 413, 419, 430, 431, 467, 491, 497, 581, 599, 623, 647, 665, 713, 728, 749, 770, 827, 836, 887, 893, 971, 1031, 1043 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..53.

MATHEMATICA

Select[Range[1, 5000], Divisible[DivisorSigma[1, #], EulerPhi[7 + #]] && ! Mod[#, 3] == 0 &] (* David Nacin, Mar 04 2012 *)

PROG

(PARI) is(n)=n%3 && sigma(n)%eulerphi(n+7)==0 \\ Charles R Greathouse IV, Sep 25 2012

CROSSREFS

Sequence in context: A266988 A248642 A121297 * A106389 A030726 A039282

Adjacent sequences:  A015845 A015846 A015847 * A015849 A015850 A015851

KEYWORD

nonn

AUTHOR

Robert G. Wilson v

STATUS

approved

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Last modified May 23 11:01 EDT 2019. Contains 323513 sequences. (Running on oeis4.)