OFFSET
1,4
COMMENTS
Apparently, the three sequences T_1(n) = Sum_{k=1..n} n^(k-1)/k!, T_2(n) = Sum_{k=0..n} n^k/k!, and T_3(n) = Sum_{k=1..n} n^k/k!, with numerators in A119029, A120266, and A120267, respectively, have the same denominators, listed in the current sequence. This, however, is not immediately obvious. - Petros Hadjicostas, May 12 2020
LINKS
Michel Marcus, Table of n, a(n) for n = 1..150
Eric Weisstein, Exponential Sum Function.
FORMULA
a(n) = n!/A214402(n).
MATHEMATICA
Denominator[Table[Sum[n^k/k!, {k, 0, n}], {n, 1, 30}]]
PROG
(PARI) a(n) = denominator(sum(k=0, n, n^k/k!)); \\ Michel Marcus, Apr 20 2021
CROSSREFS
KEYWORD
frac,nonn
AUTHOR
Jonathan Sondow, Jul 15 2012
STATUS
approved