923780

Appears in sequences

• a(n) = (2n+1)!/n!^2.at n=9A002457
• First numerator and then denominator of central elements of Leibniz's Harmonic Triangle.at n=19A046212
• Swinging factorial, a(n) = 2^(n-(n mod 2))*Product_{k=1..n} k^((-1)^(k+1)).at n=19A056040
• a(n) = n!/(k!)^2, where k is the largest number such that (k!)^2 divides n!.at n=18A056042
• Tenth column (m=9) of (1,6)-Pascal triangle A096956.at n=12A097300
• a(n) = n * binomial(n-1, floor((n-1)/2)) = n * max_{i=0..n} binomial(n-1, i).at n=19A100071
• Denominator of Sum_{i=1..n} 1/C(2*i,i).at n=11A112098
• a(n) = Fibonacci(n) * Catalan(n).at n=10A119694
• Triangle, read by rows, defined by T(n,k) = A000108(n-k)*A001147(k)*C(n,2*k), for k=0..[n/2], n>=0, where A000108 is the Catalan numbers and A001147 is the double factorials.at n=37A125080
• Product{k|n} k$. Here '$' denotes the swinging factorial function (A056040).at n=19A163087
• a(n) = 2^n*binomial((n + 1 + (n mod 2))/2, 1/2).at n=18A242172
• a(n) = (9*n+10)*binomial(n+9,9)/10.at n=10A254142
• a(n) = A(n) if n is even else a(n) = A(n)*(n-1)/(n+1) with A(n) = ((n-1)!/ floor((n-1)/2)!^2).at n=19A274707
• Expansion of (Sum_{k>=0} x^(k^4))^19.at n=25A282288
• Triangle read by rows: T(n,k) is the numerator of R(n,k) defined implicitly by the identity Sum_{i=0..l-1} Sum_{j=0..m} R(m,j)*(l-i)^j*i^j = l^(2*m+1) holding for all l,m >= 0.at n=54A302971
• Triangle read by rows: T(n, k) = (-1)^(k+1)*binomial(n,k)*binomial(n+k,k) (n >= k >= 0).at n=64A331430
• Square array T(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of sqrt(2 / ( (1-2*(k+4)*x+((k-4)*x)^2) * (1+(k-4)*x+sqrt(1-2*(k+4)*x+((k-4)*x)^2)) )).at n=54A337369
• Square array T(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of sqrt(2 / ( (1+2*(k-4)*x+((k+4)*x)^2) * (1-(k+4)*x+sqrt(1+2*(k-4)*x+((k+4)*x)^2)) )).at n=54A337464
• Triangle read by rows: T(n, k) = (-1)^(n + k)*2*binomial(2*k - 1, n)* binomial(2*n + 1, 2*k) for k > 0, and k^n for k = 0.at n=54A368846
• Triangle read by rows: T(n, k) = denominator(M(n, k)) where M is the inverse matrix of A368846.at n=54A368848