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A015831 Numbers n such that phi(n + 11) | sigma(n). 0
15, 21, 46, 69, 88, 94, 115, 119, 189, 204, 209, 210, 213, 255, 297, 329, 332, 399, 418, 465, 470, 589, 598, 609, 616, 663, 696, 749, 799, 869, 950, 1074, 1081, 1173, 1199, 1365, 1593, 1595, 1615, 1729, 1888, 1917, 2014, 2024, 2185, 2189, 2289, 2376, 2449 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..49.

MATHEMATICA

Select[Range[3000], Divisible[DivisorSigma[1, #], EulerPhi[11 + #]] &] (* David Nacin, Mar 01 2012 *)

PROG

(PARI) is(n)=!(sigma(n)%eulerphi(n+11)) \\ Charles R Greathouse IV, Sep 25 2012

CROSSREFS

Sequence in context: A171569 A247021 A129752 * A275169 A063176 A083372

Adjacent sequences:  A015828 A015829 A015830 * A015832 A015833 A015834

KEYWORD

nonn

AUTHOR

Robert G. Wilson v

STATUS

approved

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Last modified May 20 02:50 EDT 2019. Contains 323412 sequences. (Running on oeis4.)