A197952 - OEIS

%I #8 Mar 30 2012 17:35:03

%S 1033474069,1604277377,2741806637,9941342981,14754456491,14859359791,

%T 15887724883,16990353761,17266051069,20892536447,21776951239,

%U 24435763193,25165559143,32325726313,38313868379,38580669727,38856433193,47906215417,49094416289,56237053007

%N Numbers n such that sigma(phi(n))/sigma(n) = 5.

%e sigma(phi(25165559143))/sigma(25165559143) = 127671828480/25534365696 = 5.

%o (PARI) for(n=1033474069, 3*10^10, if(sigma(eulerphi(n))/sigma(n)==5, print1(n, ", ")))

%Y Cf. A033631, A066831, A067382, A067383, A067384, A067385.

%K nonn

%O 1,1

%A _Donovan Johnson_, Oct 19 2011

%E a(14)-a(20) from _Donovan Johnson_, Nov 11 2011