9694845

Appears in sequences

• Symmetrical dissections of an n-gon.at n=28A000063
• Numerators in expansion of 1/sqrt(1-x).at n=15A001790
• Numerator of n!!/(n+1)!! (cf. A006882).at n=29A004730
• Numerator of n!!/(n+3)!!.at n=29A004732
• Numerator of average distance traveled by n-dimensional fly.at n=28A004734
• a(1)=1; for n >= 1, a(n+1) = lcm(a(n),n) / gcd(a(n),n).at n=30A008339
• Catalan numbers with odd index: a(n) = binomial(4*n+2, 2*n+1)/(2*n+2).at n=7A024492
• a(n) = T(n, floor(n/2)), where T = Catalan triangle (A008315).at n=28A026008
• a(n) = floor( binomial(n, floor(n/2))/(1 + ceiling(n/2)) ) (interpolates between Catalan numbers).at n=30A028303
• a(n) = ceiling( binomial(n, floor(n/2))/(1 + ceiling(n/2)) ) (interpolates between Catalan numbers).at n=30A028304
• Denominator of rational part of Haar measure on Grassmannian space G(n,1).at n=30A036069
• Odd Catalan numbers: a(n) = A000108(2^n-1).at n=4A038003
• Numerators of Taylor series expansion of arcsin(x). Also arises from arccos(x), arccsc(x), arcsec(x), arcsinh(x).at n=15A055786
• Central binomial coefficient A001405(n) divided by its characteristic cube divisor A056201(n).at n=28A056202
• GCD of consecutive central binomial coefficients: a(n) = gcd(A001405(n+1), A001405(n)).at n=30A057977
• a(n) = mu(n) * Catalan(n).at n=15A062627
• Bisection of A001790.at n=7A063079
• Smallest number of crossing-free matchings on n points in the plane.at n=29A063549
• G.f.: A(x) = (x-2*x^2-2*x^3-(1+x)*sqrt(1-4*x^2)+sqrt(1-4*x^6))/(2*x^2).at n=28A063786
• G.f.: A(x) = (x-2*x^2-2*x^3-(1+x)*sqrt(1-4*x^2)+sqrt(1-4*x^6))/(2*x^2).at n=29A063786