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A108405 Numbers n such that a^u + b^u + c^u + ... is prime, where a*b*c* ... is the prime factorization of n and u is the largest prime dividing n. 0

%I

%S 12,28,40,48,54,80,90,96,104,108,224,350,384,390,432,500,567,570,660,

%T 686,720,770,775,810,972,1085,1176,1551,1575,1875,2016,2400,2560,2600,

%U 2700,2760,2829,2880,2925,3072,3456,3640,3645,3888,4260,4374,4400,4692

%N Numbers n such that a^u + b^u + c^u + ... is prime, where a*b*c* ... is the prime factorization of n and u is the largest prime dividing n.

%e a(2)=28 because 28=2*2*7 and 2^7 + 2^7 + 7^7 = 823799, a prime.

%Y Cf. A006530.

%K nonn

%O 1,1

%A _Jason Earls_, Jul 04 2005

%E More terms from _Ryan Propper_, Feb 11 2008

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Last modified December 7 20:30 EST 2019. Contains 329849 sequences. (Running on oeis4.)