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A099636
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a(n) = gcd(sum of distinct prime factors of n, product of distinct prime factors of n).
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7
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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, 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, 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
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OFFSET
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1,2
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LINKS
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FORMULA
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(End)
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EXAMPLE
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n=84: a(84) = gcd(2*3*7, 2+3+7) = gcd(42, 12) = 6.
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MATHEMATICA
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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 *)
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PROG
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(PARI)
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CROSSREFS
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Differs from related A099635 for the first time at n=84, where a(84) = 6, while A099635(84) = 12.
Differs from A014963 for the first time at n=30, where a(30) = 10, while A014963(30) = 1.
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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