4537567649

Appears in sequences

• a(n) = binomial(2n+1, n+1) - 1.at n=17A010763
• Central binomial coefficient - 1.at n=35A014495
• Number of nonempty subsets of {1,2,...,n} in which exactly 1/2 of the elements are <= (n-1)/2.at n=35A047171
• a(n) is the numerator of tanh(Sum_{k=1..n-1} artanh(k/n)), where artanh is the inverse hyperbolic tangent function.at n=17A382257