2540032

Appears in sequences

• Number of perfect matchings in the graph C_5 X C_{2n}.at n=3A231485
• Number of perfect matchings in the graph C_10 X C_n.at n=2A281679
• Square array T(n,k), n >= 1, k >= 1, read by antidiagonals, where T(n,k) = sqrt( Product_{a=1..n} Product_{b=1..k} (4*sin((2*a-1)*Pi/(2*n))^2 + 4*sin((2*b-1)*Pi/k)^2) ).at n=40A341533
• a(n) = sqrt(Product_{1<=j,k<=n} (4*sin((2*j-1)*Pi/(2*n))^2 + 4*sin((2*k-1)*Pi/n)^2)).at n=5A341535
• Square array T(n,k), n >= 1, k >= 1, read by antidiagonals downwards: number of perfect matchings in the graph C_{2n} x C_k.at n=40A341741