A015850 Numbers k such that phi(k + 12) | sigma(k) for k not congruent to 0 (mod 3).

14, 23, 38, 109, 248, 280, 380, 406, 506, 1178, 1288, 1364, 1504, 1528, 1798, 1976, 1978, 1990, 2408, 2528, 2698, 3160, 3230, 4318, 4888, 6106, 6904, 7160, 7192, 7366, 8234, 8648, 8804, 8920, 8932, 9238, 10726, 10856, 11210, 11684, 11818, 12008, 12154, 14212

Offset

1,1

Links

Table of n, a(n) for n=1..44.

Mathematica

Select[Range[1, 10000], Divisible[DivisorSigma[1, #], EulerPhi[12 + #]] && !Mod[#, 3] == 0 &] (* David Nacin, Mar 04 2012 *)

Prog

(PARI) is(n)=n%3 && sigma(n)%eulerphi(n+12)==0 \\ Charles R Greathouse IV, Sep 25 2012

Crossrefs

Sequence in context: A010922 A010902 A010923 * A020905 A048635 A114872

Adjacent sequences: A015847 A015848 A015849 * A015851 A015852 A015853

Keyword

nonn

Author

Robert G. Wilson v

Status

approved