3016365domain: NAppears in sequencesOdd numbers with exactly 5 distinct palindromic prime factors.at n=25A046407a(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).at n=4A340139