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%I #13 Apr 06 2020 03:11:12
%S 1,12,540,1024,1072,1092,1320,1408,4272,16200,29568,40082,43740,56592,
%T 123192,251736,265440,276000,664320,725760,758560,771264,2101248,
%U 3195192,6592704,7243050,7464960,8755680,10553502,11715840,14135296,19952730,20058720,21672288
%N Numbers k such that phi(prime(k)-1) == 0 (mod k).
%t Select[Range[42000], Mod[EulerPhi[Prime[ # ] - 1], # ] == 0 &]
%o (PARI) for(k=1,2600000, if(eulerphi(prime(k)-1)%k==0,print1(k,",")))
%Y Cf. A000010, A006093, A008330.
%K nonn
%O 1,2
%A _Benoit Cloitre_, Feb 05 2002
%E More terms from _Klaus Brockhaus_, Feb 13 2002
%E More terms from _Jinyuan Wang_, Apr 05 2020