A015820 Numbers k such that phi(k + 4) | sigma(k).

5, 6, 10, 14, 22, 24, 34, 35, 38, 58, 66, 70, 82, 95, 110, 118, 120, 140, 142, 143, 191, 202, 214, 224, 228, 230, 255, 274, 276, 298, 308, 351, 358, 374, 376, 382, 394, 454, 478, 538, 562, 570, 590, 598, 616, 620, 622, 623, 694, 728, 744, 780, 838, 862, 864

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Mathematica

Select[Range[1000], Divisible[DivisorSigma[1, #], EulerPhi[4 + #]] &] (* David Nacin, Mar 01 2012 *)

Prog

(PARI) is(n)=sigma(n)%(eulerphi(n)+4)==0 \\ Charles R Greathouse IV, Sep 25 2012

Crossrefs

Sequence in context: A005847 A109758 A287665 * A096728 A329271 A011985

Adjacent sequences: A015817 A015818 A015819 * A015821 A015822 A015823

Keyword

nonn

Author

Robert G. Wilson v

Status

approved