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A116046 n+phi(n)+phi(phi(n)) is a semiprime (A001358). 1

%I #2 Mar 30 2012 17:40:36

%S 2,3,6,7,8,11,14,18,23,27,29,31,34,37,38,42,45,47,53,55,59,63,65,66,

%T 69,73,74,83,89,90,91,93,103,105,107,109,110,117,119,123,125,127,129,

%U 130,131,138,139,143,145,150,151,157,167,174,175,179,182,183,185,186

%N n+phi(n)+phi(phi(n)) is a semiprime (A001358).

%e 103+phi(103)+phi(phi(103)) = 3*79.

%Y Cf. A001358, A116045.

%K nonn

%O 1,1

%A _Giovanni Resta_, Feb 13 2006

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Last modified September 15 18:02 EDT 2024. Contains 375954 sequences. (Running on oeis4.)