OFFSET
1,2
REFERENCES
Ovidiu Furdui, Limits, Series, and Fractional Part Integrals: Problems in Mathematical Analysis, New York: Springer, 2013. See Problem 3.114, p. 146 and 240-241.
LINKS
Ivan Panchenko, Table of n, a(n) for n = 1..1000
Université de La Rochelle, L2 - MG 2 - TD 5 - Exercice 4 (2020-2021).
FORMULA
Equals Sum_{m>=0} Sum_{k=0..m} (-1)^(m-k) / (k! * 2^(m-k)). - Bernard Schott, Oct 02 2021
Equals Sum_{n,m>=1} n*m/(n+m)! (Furdui, 2013). - Amiram Eldar, Mar 26 2022
EXAMPLE
1.81218788563936349024...
MATHEMATICA
RealDigits[2*E/3, 10, 100][[1]] (* Amiram Eldar, Mar 26 2022 *)
PROG
(PARI) 2*exp(1)/3 \\ Michel Marcus, Mar 26 2022
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
STATUS
approved