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%I #11 Apr 14 2022 14:02:46
%S 56,476,2840,4676,8120,9416,16256,23940,25056,28520,30566,32760,36146,
%T 37716,39816,55676,56306,65280,66056,129260,135840,143096,149960,
%U 155876,176736,185240,198240,198396,202676,232596,252756,257312,296786
%N Numbers n such that phi(4n+1) = sigma(n).
%C Are there any odd terms in the sequence?
%H Donovan Johnson, <a href="/A067234/b067234.txt">Table of n, a(n) for n = 1..1000</a>
%t Select[Range[300000],EulerPhi[4#+1]==DivisorSigma[1,#]&] (* _Harvey P. Dale_, Apr 14 2022 *)
%o (PARI) for(n=1, 10^9, if(eulerphi(4*n+1)==sigma(n), print(n))) /* _Donovan Johnson_, Aug 18 2012 */
%K nonn
%O 1,1
%A _Benoit Cloitre_, Feb 20 2002
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