152787181domain: NAppears in sequencesa(n) = 2*a(n-1)+15*a(n-2) with n>0, a(0)=0, a(1)=1.at n=13A079773Zsigmondy numbers for a = 5, b = 3: Zs(n, 5, 3) is the greatest divisor of 5^n - 3^n (A005058) that is relatively prime to 5^m - 3^m for all positive integers m < n.at n=25A109347