OFFSET
1,2
EXAMPLE
n=5: (2+2)/2*2+(2+3)/2*3+(3+3)/3*3+(2+5)/2*5+(2+7)/2*7 =
4/4 + 5/6 + 6/9 + 7/10 + 9/14 = 269/70 = A120831(5)/a(5).
CROSSREFS
KEYWORD
nonn,frac
AUTHOR
Reinhard Zumkeller, Jul 24 2006
STATUS
approved