1485824domain: NAppears in sequencesSurround numbers of an n X 2 rectangle when n is even.at n=30A061524a(n) = 4^n cos(nC), where C is the angle opposite side AB in a triangle ABC having sidelengths |BC|=2, |CA| = 3, |AB| = 4; ABC is the smallest integer-sided scalene triangle.at n=11A375882