A015848 Numbers k such that phi(k + 7) | sigma(k) for k not congruent to 0 (mod 3).

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

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