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)).

A341535

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)).

Terms

    a(0) =1a(1) =2a(2) =36a(3) =224a(4) =38416a(5) =2540032a(6) =4115479104

External references