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A099636 a(n) = gcd(sum of all prime factors of n, product of all prime factors of n). 2

%I

%S 1,2,3,2,5,1,7,2,3,1,11,1,13,1,1,2,17,1,19,1,1,1,23,1,5,1,3,1,29,10,

%T 31,2,1,1,1,1,37,1,1,1,41,6,43,1,1,1,47,1,7,1,1,1,53,1,1,1,1,1,59,10,

%U 61,1,1,2,1,2,67,1,1,14,71,1,73,1,1,1,1,6,79,1,3,1,83,6,1,1,1,1,89,10,1,1,1

%N a(n) = gcd(sum of all prime factors of n, product of all prime factors of n).

%e n=84: a(84) = gcd(2*3*7, 2+3+7) = gcd(42, 12) = 6.

%t PrimeFactors[n_Integer] := Flatten[ Table[ # [[1]], {1}] & /@ FactorInteger[n]]; f[n_] := Block[{pf = PrimeFactors[n]}, GCD[Plus @@ pf, Times @@ pf]]; Table[ f[n], {n, 93}] (* _Robert G. Wilson v_, Nov 04 2004 *)

%Y Cf. A099634, A099635.

%K nonn

%O 1,2

%A _Labos Elemer_, Oct 28 2004

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Last modified October 22 19:55 EDT 2020. Contains 337954 sequences. (Running on oeis4.)