OFFSET
1,1
COMMENTS
Koninck & Luca give upper and lower bounds for the number of elements of this sequence below x: x / exp(c_i(1 + o(1))sqrt(log x log log x)), where the constants c_i and the o(1) differ for lower and upper bounds. - Charles R Greathouse IV, Sep 08 2012
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
Jean-Marie de Koninck, Florian Luca, Integers divisible by the sum of their prime factors, Mathematika 52 (1&2) (2005) 69-77, MR2261843.
EXAMPLE
MAPLE
MATHEMATICA
Select[Range[2, 540], !PrimeQ[#]&&IntegerQ[#/Total[First/@FactorInteger[#]]]&] (* Jayanta Basu, Jun 02 2013 *)
PROG
(PARI) is(n)=my(f=factor(n)[, 1]); n%sum(i=1, #f, f[i])==0 \\ Charles R Greathouse IV, Feb 04 2013
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
R. J. Mathar, Mar 27 2009
STATUS
approved