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A099635 a(n) = gcd(sum of all prime factors of n, n). 4
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, 12, 1, 1, 1, 1, 89, 10, 1, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
a(n) = n iff n is prime. - Robert Israel, Mar 29 2015
LINKS
EXAMPLE
a(25) = gcd(5,25) = 5.
MAPLE
seq(igcd(n, convert(numtheory:-factorset(n), `+`)), n = 1 .. 1000); # Robert Israel, Mar 29 2015
MATHEMATICA
PrimeFactors[n_Integer] := Flatten[ Table[ # [[1]], {1}] & /@ FactorInteger[n]]; f[n_] := GCD[Plus @@ PrimeFactors[n], n]; Table[ f[n], {n, 93}] (* Robert G. Wilson v, Nov 04 2004 *)
CROSSREFS
Sequence in context: A020500 A014963 A099636 * A178380 A178375 A086847
KEYWORD
nonn
AUTHOR
Labos Elemer, Oct 28 2004
STATUS
approved

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Last modified February 29 20:48 EST 2024. Contains 370428 sequences. (Running on oeis4.)