Combinatorics / CONCEPT

Walks of near-maximal algebraic area on the square lattice

For k < n, the 2n-step walks on the square lattice with algebraic area n^2 - k number twice the coefficient of x^k in phi(x)/f(-x), and the (2n+1)-step walks with area n^2 + n - k number four times the coefficient of x^k in psi(x^2)/f(-x).