generating function for the reciprocal central binomial coefficients
It is well known that the sequence called central binomial coefficients
is defined by and whose initial terms are has a generating function .But it is less known the fact thatthe function
has ordinary power series
This means that such a function is a generating function for the reciprocals .
From that expression we can see that the numerical series sums which has the approximate value .
Reference:
1) Renzo Sprugnoli, Sum of reciprocals of the Central Binomial Coefficients, Integers: electronicjournal of combinatorial number theory, 6 (2006) A27, 1-18