203212800

Appears in sequences

• Multiply successively by 1,1,2,2,3,3,4,4,..., n >= 1, a(0) = 1.at n=15A010551
• a(n) = n!*(n+1)!.at n=7A010790
• Product of consecutive factorials.at n=21A034882
• Expansion of e.g.f. 1/(1-2*x^2-x^3).at n=10A052684
• Triangle T(n,k) generalizing the tangent numbers.at n=26A064190
• Symmetric triangle of certain normalized products of decreasing factorials.at n=47A090441
• a(n) = 2(m!)^2 for n = 2m and m!(m+1)! for n = 2m+1.at n=15A092186
• Number of deco polyominoes of height n, having no 2-cell columns starting at level 0. A deco polyomino is a directed column-convex polyomino in which the height, measured along the diagonal, is attained only in the last column.at n=11A121635
• Coefficients of the v=1 member of a family of certain orthogonal polynomials.at n=37A129065
• A triangular sequence from umbral calculus expansion of _Simon Plouffe_'s rational polynomial for A002890: p(x,t) = exp(x*t)*(1 - 6*t + 9*t^2 - 4*t^3 + t^4)/(4*t - 1)/(2*t - 1).at n=46A137514
• Triangle read by rows: T(n,k) = n!*k!, 0 <= k <= n.at n=43A143216
• Erroneous version of A010790.at n=6A143248
• Number of permutations of {1,2,...,n} (n>=2) having a single run of even entries. For example, the permutation 513284679 has a single run of even entries: 2846.at n=12A152873
• The pg(n) sequence that is associated with the Eta triangle A160464.at n=6A162440
• Number of permutations of {1,2,3,...,n} such that no even numbers are adjacent.at n=14A258213
• a(n) = Product_{i=1..n} i*rad(i) where rad(n) = A007947(n).at n=8A277174
• Numbers that can be written as a product of two or more consecutive factorial numbers.at n=13A334174
• Number of graceful labelings of the complete bipartite graph K_{n,n}.at n=6A337793
• Numbers with a record number of non-unitary square divisors.at n=26A358253
• Triangle read by rows, T(n, k) = RisingFactorial(n - k, k) * FallingFactorial(n, k).at n=43A362588