1247400

Appears in sequences

• a(n) = (2n+1)! / 2^n.at n=5A007019
• Expand sin x / exp x = x-x^2+x^3/3-x^5/30+... and invert nonzero coefficients.at n=11A007415
• Denominators of expansion of exp x / sin x.at n=10A007451
• Expand cos x / exp x and invert nonzero coefficients.at n=11A007452
• Expansion of E.g.f.: (1 + x)/(1 + x + x^2/2).at n=11A009014
• Denominators of Taylor series for exp(x)*sin(x).at n=11A046979
• Denominators of Taylor series for exp(x)*cos(x).at n=11A046981
• Triangle of number of permutations of {1, 2, ..., n} having exactly k cycles, each of which is of length >=r for r=4.at n=14A050212
• Triangle T(n,k) of k-block ordered bicoverings of an unlabeled n-set, n >= 2, k = 3..n+floor(n/2).at n=36A060092
• For n >= 1 a(n) is the size of the conjugacy class in the symmetric group S_(4n) consisting of permutations whose cycle decomposition is a product of n disjoint 4-cycles.at n=3A060706
• Denominators of coefficients of expansion of sinh(x)/sin(x) (even powers only).at n=5A069854
• a(n) = n! / 2^floor(n/2).at n=11A090932
• Number of meaningfully different ways to design a neutral single-elimination tournament with n teams.at n=10A096351
• Partial products of largest prime factors of numbers <= n.at n=11A104350
• Euler's totient of A104365(n) = A104350(n) + 1.at n=11A104371
• a(2) = 1 by definition; otherwise a(n) = A109347(n)/n.at n=7A110348
• Triangle, read by rows, where T(n,k) = n!/(k!*(n-4*k)!*4^k) for n>=4*k>=0.at n=27A118933
• Where records occur in A144262.at n=12A144376
• Triangle T(n,k) read by rows: number of k-lists (ordered k-sets) of disjoint 2-subsets of an n-set, n>1, 0<k<=floor(n/2).at n=33A157018
• Triangle T(n,k) read by rows: number of k-lists (ordered k-sets) of disjoint 2-subsets of an n-set, n>1, 0<k<=floor(n/2).at n=29A157018