OFFSET
1,2
COMMENTS
Conjecture: sequence is injective (all terms of this sequence occur only once).
LINKS
Jaroslav Krizek, Table of n, a(n) for n = 1..100
FORMULA
a(n) = sum_(d|n) (product_(d|n) d) / (product_( d_x|n , d_x<=d) d_x) = sum_(d|n) (A007955(n)) / (product_( d_x|n , d_x<=d) d_x).
a(p) = p + 1 for prime p.
EXAMPLE
The divisors of 6 are 1, 2, 3, 6.
So a(6) is the numerator of 1/1+1/(1*2)+1/(1*2*3)+1/(1*2*3*6)=61/36.
a(6) = 36/1+36/(1*2)+36/(1*2*3)+36/(1*2*3*6)=36+18+6+1=61.
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Dec 22 2012
STATUS
approved