a(n) = 4^((n-2)*(n-1)) * Product_{1<=i<j<=n-1} (1 - sin(i*Pi/(2*n))^2 * sin(j*Pi/(2*n))^2).
A340139
a(n) = 4^((n-2)*(n-1)) * Product_{1<=i<j<=n-1} (1 - sin(i*Pi/(2*n))^2 * sin(j*Pi/(2*n))^2).
Terms
- a(0) =1a(1) =1a(2) =13a(3) =1904a(4) =3016365a(5) =50771120400
External references
- oeis: A340139