A067878 - OEIS

%I #8 Feb 02 2015 15:02:03

%S 1,10,33,46,65,77,123,136,221,371,385,423,513,532,545,572,660,702,753,

%T 1248,1566,1643,1720,2033,2635,3243,4533,4798,5177,5346,5495,5605,

%U 6460,7463,7565,7683,7739,8201,9342,9741,10780,10792,11679,11880,12256

%N Numbers n such that sigma(n)=phi(n*omega(n)-1).

%C Omega(n) refers to unique prime factors of n, i.e., prime factors taken without multiplicity. - _Harvey P. Dale_, Feb 02 2015

%t Select[Range[13000],DivisorSigma[1,#]==EulerPhi[#*PrimeNu[#]-1]&] (* _Harvey P. Dale_, Feb 02 2015 *)

%K easy,nonn

%O 1,2

%A _Benoit Cloitre_, Mar 02 2002