Search: id:A075867
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%I A075867
%S A075867 4,12,18,27,40,180,250,300,450,704,780,924,1120,1170,1320,1344,1386,
%T A075867 1400,1950,1960,2025,2970,3125,3192,3234,3500,4080,4455,4725,4760,4896,
%U A075867 5070,5082,5625,5720,6615,6860,7182,7280,7875,8250,8280,8505,8704
%N A075867 tau(n) = sigma(sum of prime factors of n).
%e A075867 tau(40) = number of divisors of 40 = 8; sigma(sum of prime factors of 
               40) = sigma(2 + 5) = 8. Hence 40 is a term of the sequence.
%t A075867 Select[Range[2, 10^4], DivisorSigma[1, Apply[Plus, Transpose[FactorInteger[ 
               # ]][[1]]]] == DivisorSigma[0, # ] &]
%Y A075867 Sequence in context: A074285 A057311 A063679 this_sequence A071929 A008037 
               A062859
%Y A075867 Adjacent sequences: A075864 A075865 A075866 this_sequence A075868 A075869 
               A075870
%K A075867 nonn
%O A075867 2,1
%A A075867 Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Oct 15 2002

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