login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A099635 a(n) = gcd(sum of all prime factors of n, n). 3
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

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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 22 17:16 EDT 2020. Contains 337291 sequences. (Running on oeis4.)