-1973250943domain: ZAppears in sequencesa(n) = 2^(n+1)*cos(n*arctan(sqrt(15))).at n=32A272931a(n) = 2^(2n+1)*cos(nA), where A is the angle opposite side BC in a triangle ABC having sidelengths |BC|=2, |CA| = 3, |AB| = 4; ABC is the smallest integer-sided scalene triangle.at n=16A375880