
COMMENTS

Number of walks in 4dimensions using steps (1,0,0,0), (0,1,0,0), (0,0,1,0) and (0,0,0,1) from (0,0,0,0) to (n,n,n,n) such that after each step we have y>=x.
Number of possible necklaces consisting of n white beads, n1 red beads, n1 green beads, and n1 blue beads (two necklaces are considered equivalent if they differ by a cyclic permutation).
Note: the generalizations of this formula and the relation between ddimensional walks and dcolored necklaces are also true for all d, d>=5.
