A164647 - OEIS

%I #7 Jul 14 2012 11:32:31

%S 1463,2945,8255,70091,81809,89999,122759,187625,193039,196469,388585,

%T 494665,671365,2311673,2442583,2687113,4209985,4705285,4902247,

%U 5393017,5667389,5866003,9248323,10795967,11345411,11670275,11773027,13290485,13741273,15978487

%N Numbers n such that sigma(n)/phi(n) = 16/9.

%C A subsequence of A011257.

%H Donovan Johnson, <a href="/A164647/b164647.txt">Table of n, a(n) for n = 1..1000</a>

%o (PARI) for( n=1,10^7, sigma(n)==16/9*eulerphi(n) && print1(n","))

%Y Cf. A000010 (=phi), A000203 (=sigma), A068390, A163667, A164646.

%K nonn

%O 1,1

%A _M. F. Hasler_, Aug 22 2009

%E More terms from _Farideh Firoozbakht_, Sep 22 2009