A139316 An integer k, k>=2, is in the sequence if A001222(k) (the sum of the exponents in the prime factorization of k) divides A008472(k) (the sum of the distinct primes dividing k).

2, 3, 4, 5, 7, 11, 13, 15, 17, 19, 21, 23, 27, 28, 29, 31, 33, 35, 37, 39, 41, 42, 43, 47, 48, 51, 52, 53, 55, 57, 59, 61, 65, 67, 69, 71, 72, 73, 76, 77, 78, 79, 83, 84, 85, 87, 89, 91, 93, 95, 97, 98, 101, 103, 105, 107, 108, 109, 110, 111, 113, 114, 115, 119, 120, 123

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

28 has the prime factorization 2^2 * 7^1. The sum of the exponents, 2+1 = 3, divides the sum of the distinct prime divisors, 2+7 = 9. So 28 is in the sequence.

Mathematica

seddpQ[n_]:=Module[{fi=Transpose[FactorInteger[n]]}, Divisible[Total[ fi[[1]]], Total[ fi[[2]]]]]; Select[Range[2, 150], seddpQ] (* Harvey P. Dale, Apr 13 2015 *)

Crossrefs

Cf. A001222, A008472.

Sequence in context: A191876 A234719 A055464 * A062972 A231878 A285304

Adjacent sequences: A139313 A139314 A139315 * A139317 A139318 A139319

Keyword

nonn

Author

Leroy Quet, Jun 07 2008

Extensions

More terms from D. S. McNeil, Mar 23 2009

Status

approved