Pandiagonal Sudokus

Abstract

It is shown that a pandiagonal $n^2\times n^2$-Sudoku exists if and only if $n \equiv \pm 1~($mod$~6)$. Also for these $n$ the existence of row-cyclic, pandiagonal $n^2\times n^2$-Sudokus is conjectured and confirmed for $n=5$ and $n=7$.