A099635 a(n) = gcd(sum of all prime factors of n, n).

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

Offset

1,2

Comments

a(n) = n iff n is prime. - Robert Israel, Mar 29 2015

Links

Robert Israel, Table of n, a(n) for n = 1..10000

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

Cf. A099634, A099636.

Sequence in context: A020500 A014963 A099636 * A178380 A178375 A086847

Adjacent sequences: A099632 A099633 A099634 * A099636 A099637 A099638

Keyword

nonn

Author

Labos Elemer, Oct 28 2004

Status

approved