84284domain: NAppears in sequencesa(n) = Jacobi P-Polynomial P_n(alpha=1, beta=1, x=sqrt(2)) multiplied by 2^(n/2+floor(n/2)) and divided by n+1.at n=9A025176Number of polygons formed when every pair of vertices of a row of n adjacent congruent rectangles are joined by an infinite line.at n=22A344993