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%I #10 Jan 02 2017 05:13:23
%S 1,5,221,763,2759,11303,12749,13079,20677,33725,42253,75101,96193,
%T 140225,160369,168113,171667,195889,227099,229969,269161,275971,
%U 316129,344317,385033,387163,392677,437999,498253,528209,562913,611381,661181
%N Numbers n such that phi(sigma(phi(n))) = sigma(n).
%H Harry J. Smith, <a href="/A066462/b066462.txt">Table of n, a(n) for n = 1..771</a>
%t Select[Range[1, 10^6], EulerPhi[DivisorSigma[1, EulerPhi[ # ]]] == DivisorSigma[1, # ] &]
%o (PARI) { n=0; for (m=1, 10^9, if (eulerphi(sigma(eulerphi(m))) == sigma(m), write("b066462.txt", n++, " ", m); if (n==1000, return)) ) } \\ _Harry J. Smith_, Feb 16 2010
%K nonn
%O 1,2
%A _Joseph L. Pe_, Jan 02 2002
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