Search: id:A071140
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%I A071140
%S A071140 30,60,70,90,120,140,150,180,240,270,280,286,300,350,360,450,480,490,
%T A071140 540,560,572,600,646,700,720,750,810,900,960,980,1080,1120,1144,1200,
%U A071140 1292,1350,1400,1440,1500,1620,1750,1798,1800,1920,1960,2160,2240,2250
%N A071140 Sum of distinct primes dividing n is divisible by largest prime dividing 
               n; n is neither a prime, nor a true power of prime.
%F A071140 A008472(n)/A006530(n) is integer and n has at least 3 distinct prime 
               factors.
%e A071140 n=70=2.5.7 has a form of 2pq, where p and q are twin primes; n=3125=3.5.11.19, 
               sum=3+5+11+19=38=2.19, divisible by 19.
%t A071140 ffi[x_] := Flatten[FactorInteger[x]] lf[x_] := Length[FactorInteger[x]] 
               ba[x_] := Table[Part[ffi[x], 2*w-1], {w, 1, lf[x]}] sb[x_] := Apply[Plus, 
               ba[x]] ma[x_] := Part[Reverse[Flatten[FactorInteger[x]]], 2] Do[s=sb[n]/
               ma[n]; If[IntegerQ[s]&&Greater[s, 1], Print[{n, ba[n]}]], {n, 2, 
               1000000}]
%Y A071140 Cf. A008472, A006530, A000961, A025475, A037074, A071139-A071147.
%Y A071140 Sequence in context: A051488 A051283 A066031 this_sequence A074915 A056954 
               A050519
%Y A071140 Adjacent sequences: A071137 A071138 A071139 this_sequence A071141 A071142 
               A071143
%K A071140 nonn
%O A071140 1,1
%A A071140 Labos E. (labos(AT)ana.sote.hu), May 13 2002

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