OFFSET
1,2
COMMENTS
Hall shows that the density of this sequence is 6/Pi^2, so a(n) ~ (Pi^2/6)n.
Differs from A267114, from A030231, and from A007774 (shifted by one index) first at n=93. - R. J. Mathar, Aug 22 2016
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
R. B. Hall, On the probability that n and f(n) are relatively prime, Acta Arithmetica 17 (1970), pp. 169-183.
MATHEMATICA
Select[Range@ 165, CoprimeQ[#, Total@ FactorInteger[#][[All, 1]]] &] (* Michael De Vlieger, Aug 06 2016 *)
PROG
(PARI) sopf(n)=vecsum(factor(n)[, 1])
is(n)=gcd(sopf(n), n)==1
CROSSREFS
KEYWORD
nonn
AUTHOR
Charles R Greathouse IV, Aug 04 2016
STATUS
approved