Comment on Volume 16(1), article R72 (Jun 19, 2009)

Counting Abelian Squares L. B. Richmond and Jeffrey Shallit

Comment by the second author, Dec 16, 2009:

Thomas Prellberg has kindly pointed out that yet another proof of our Theorem 4 can be found in:

A. J. Guttman and T. Prellberg,

Staircase polygons, elliptic integrals, Heun functions, and lattice Green functions,

Physical Review E 47 (4) (1993), R2233-R2236.