OFFSET
0,2
COMMENTS
Does a(n+1)/a(n) converge?
LINKS
Hiroaki Yamanouchi, Table of n, a(n) for n = 0..19
EXAMPLE
The first 10^2 terms in A097974 sum to 327, so a(2) = 327.
MATHEMATICA
s = 0; k = 1; Do[s += Plus @@ Select[Select[Divisors[n], PrimeQ], #<=Sqrt[n] &]; If[n == k, Print[s]; s = 0; k *= 10], {n, 1, 10^7}]
PROG
(PARI) a(n) = sum(m=1, 10^n, sumdiv(m, d, d*isprime(d)*(d<=sqrt(m)))); \\ Michel Marcus, Jul 07 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Ryan Propper, Jul 24 2005
EXTENSIONS
a(2)-a(7) and the example corrected and a(8)-a(16) from Hiroaki Yamanouchi, Jul 07 2014
STATUS
approved