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A015845 Numbers n such that phi(n) | sigma(n + 7). 6
1, 2, 3, 4, 5, 6, 7, 8, 12, 16, 20, 22, 24, 26, 27, 28, 31, 35, 39, 40, 50, 58, 63, 70, 88, 95, 108, 112, 116, 120, 135, 152, 163, 183, 224, 228, 241, 273, 315, 323, 364, 369, 455, 476, 520, 524, 616, 620, 632, 703, 782, 855, 903, 945, 950, 1008, 1124, 1188 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Ivan Neretin, Table of n, a(n) for n = 1..1000

MATHEMATICA

Select[Range[3000], Divisible[DivisorSigma[1, 7 + #], EulerPhi[#]] &]  (* David Nacin, Mar 03 2012 *)

PROG

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

CROSSREFS

Sequence in context: A238084 A211202 A066418 * A030702 A305926 A033087

Adjacent sequences:  A015842 A015843 A015844 * A015846 A015847 A015848

KEYWORD

nonn

AUTHOR

Robert G. Wilson v

EXTENSIONS

a(1) = 1 added by Ivan Neretin, Feb 05 2017

STATUS

approved

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Last modified April 23 21:25 EDT 2019. Contains 322388 sequences. (Running on oeis4.)