10802495488domain: NAppears in sequencesa(n) is the numerator of the real part of 1/(1+i/2)^n, where i is the imaginary unit.at n=16A370191a(n) = 20^n * cos(n*A), where A is the angle opposite side BC in a triangle ABC having sidelengths |BC|=3, |CA|=4, |AB|=5; ABC is the smallest integer-sided right triangle.at n=8A376285