OFFSET
0,3
EXAMPLE
n=0: the empty sum is 0 by convention, so a(0)=1.
n=1: the sum is 1, so a(1)=1.
n=2: the sum is 1 + 1/2 = 3/2 so a(2) = 2.
MATHEMATICA
Join[{1}, Accumulate[Table[n!/n^2, {n, 40}]]//Denominator] (* Harvey P. Dale, May 11 2019 *)
PROG
(PARI) a(n) = denominator(sum(i=1, n, i!/i^2)); \\ Michel Marcus, Mar 18 2018
CROSSREFS
KEYWORD
easy,frac,nonn
AUTHOR
Jonathan Vos Post, Aug 07 2006
STATUS
approved