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%I #11 Jul 14 2021 08:49:08
%S 750,5022,8037,18250,60249,105669,1760490,1965270,4626489,62546070,
%T 202631245,441416073,286952692809
%N Numbers k such that phi(k) equals the product of two numbers: sums of prime factors of k, with and without repetition.
%C 25446095286407049 and 27093686218810118911929 are terms.
%e 750 = 2*3*5^3 is a term since phi(750) = 200 = (2+3+5) * (2+3+5+5+5).
%t Select[Range[2, 10^5], (f=FactorInteger@#; EulerPhi[#] == Total[First /@ f]* Total[Times @@@ f]) &]
%Y Cf. A000010, A001414, A008472, A073396.
%K nonn
%O 1,1
%A _Giovanni Resta_, Feb 13 2014
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