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Numbers k such that sigma(k) = phi(k*bigomega(k)).
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%I #10 May 04 2024 13:33:59

%S 248,357,1045,3596,3956,4064,5396,8636,20026,20320,23374,24871,25714,

%T 29029,33915,35074,39585,41656,50065,55154,56134,56536,58435,61344,

%U 64285,74613,79000,87087,87685,137885,140335,142240

%N Numbers k such that sigma(k) = phi(k*bigomega(k)).

%C Comment from Giovanni Resta, Nov 15 2006: For all the numbers listed, gcd(n!-1,2^n+1) = 2n+1. Is this always true? Reply from Max Alekseyev, Nov 16 2006: This is plausible and true for n up to 45000.

%K easy,nonn

%O 1,1

%A _Benoit Cloitre_, Mar 02 2002