1288287

Appears in sequences

• Successive denominators of Wallis's approximation to Pi/2 (reduced).at n=13A001902
• Number of walks on square lattice. Column y=1 of A052174.at n=12A005559
• Number of walks on square lattice. Column y=2 of A052174.at n=11A005560
• a(n) is the number of walks from (0,0) to (0,1) that remain in the upper half-plane y >= 0 using (2*n - 1) unit steps either up (U), down (D), left (L) or right (R).at n=6A145600
• Triangle T(n,m) = (A006882(2*n + 1))^2 / ( A006882(2*m+1) * A006882(2*n-2*m+1) ).at n=23A153512
• Triangle T(n,m) = (A006882(2*n + 1))^2 / ( A006882(2*m+1) * A006882(2*n-2*m+1) ).at n=25A153512
• Denominators of the column sums of the BG2 matrix.at n=6A161736
• Triangle T(n,k) = binomial(2*n-k, k)*binomial(n+k, 2*k), read by rows.at n=49A171822
• Triangle T(n,k) = binomial(2*n-k, k)*binomial(n+k, 2*k), read by rows.at n=50A171822
• Numerators of coefficients in the series expansion of ((2 - m) EllipticK(m) - 2 EllipticE(m))/(Pi * m).at n=7A189805
• Denominator of 2n/v(n)^2, where v(1) = 0, v(2) = 1, and v(n) = v(n-1)/(n-2) + v(n-2) for n >= 3. (Limit of 2n/v(n)^2 is Pi.)at n=13A239225
• a(n) = Catalan(n)^2*n.at n=7A268085
• Array read by ascending antidiagonals: A(n, k) = (n + 1)*binomial(2*k + n - 1, k - 1)^2 / (2*k + n - 1) for k > 0, and A(n, 0) = 0.at n=43A378062
• a(n) = numerator(r(n)) where r(n) = (n/2)*(Pi/2)^cos(Pi*(n-1))*((n/2-1/2)!/(n/2)!)^2.at n=14A380949