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%I #5 Feb 25 2013 04:48:38
%S 1,3,5,18,32,36,92,144,368,576,712,800,888,918,928,1472,3193,4600,
%T 4768,8800,9288,10602,13032,16172,21204,26856,36864,56832,61792,84816,
%U 93176,94208,96768,160416,229888,339264,441440,589824,670746,746334,834048,893268
%N Values of n such that (sigma(sigma(n))-phi(phi(n)))/n is an integer (the corresponding integral ratios are given in A136132).
%H Donovan Johnson, <a href="/A136131/b136131.txt">Table of n, a(n) for n = 1..92</a> (terms < 10^10)
%e n = 92 is in the sequence because sigma(sigma(92))-phi(phi(92) = sigma(168)-phi(44) = 480-20 = 460 = 5*92.
%p with(numtheory): a:=proc(n) if type((sigma(sigma(n))-phi(phi(n)))/n, integer) =true then n else end if end proc: seq(a(n),n=1..100000);
%Y Cf. A136132, A138154, A137600.
%K nonn
%O 1,2
%A _Emeric Deutsch_, Mar 03 2008
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