6116566755domain: NAppears in sequencesNumerators of coefficients of 1/2^(2n+1) in Newton's series for Pi.at n=23A054387Numerator of Catalan(n)/2^(2n+1). Also, numerators of (2n-1)!!/(n+1)!. Odd part of the n-th Catalan number.at n=21A098597Numerator of moments of Chebyshev U- (or S-) polynomials.at n=42A134828