208012

Appears in sequences

• Symmetrical dissections of an n-gon.at n=22A000063
• Symmetrical dissections of an n-gon.at n=21A000063
• Expansion of (sqrt(1-4x^2) - sqrt(1-4x))/(2x).at n=12A000912
• Coefficients of Legendre polynomials.at n=5A001797
• Triangle of coefficients of expansions of powers of x in terms of Legendre polynomials P_n(x) over common denominator.at n=43A008317
• Incorrect version of A035010.at n=10A019275
• a(n) = T(n, floor(n/2)), where T = Catalan triangle (A008315).at n=22A026008
• a(n) = floor( binomial(n, floor(n/2))/(1 + ceiling(n/2)) ) (interpolates between Catalan numbers).at n=24A028303
• a(n) = ceiling( binomial(n, floor(n/2))/(1 + ceiling(n/2)) ) (interpolates between Catalan numbers).at n=24A028304
• Number of necklaces with 12 black beads and n-12 white beads.at n=13A032197
• Number of prime binary rooted trees with n external nodes.at n=11A035010
• Catalan numbers with even index (A000108(2*n), n >= 0): a(n) = binomial(4*n, 2*n)/(2*n+1).at n=6A048990
• GCD of consecutive central binomial coefficients: a(n) = gcd(A001405(n+1), A001405(n)).at n=24A057977
• Smallest number of crossing-free matchings on n points in the plane.at n=23A063549
• 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=23A063786
• 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=22A063786
• Smallest Catalan number (A000108) divisible by n.at n=22A066563
• Smallest Catalan number (A000108) divisible by n.at n=27A066563
• Triangle of C(n+1,k)*C(2*n-3*k,n-3*k)/(n+1) by rows.at n=30A073187
• Number of fixed points in range [A014137(n-1)..A014138(n-1)] of permutation A089864.at n=25A089408