A209185 Number of words, either empty or beginning with the first letter of the cyclic 6-ary alphabet, where each letter of the alphabet occurs n times and letters of neighboring word positions are equal or neighbors in the alphabet.

1, 2, 202, 53768, 19341130, 8151741752, 3795394507240, 1892725627422240, 992594962274742090, 540969426319412656280, 303934170379321788972952, 175019302819674622982714912, 102858166922334018149414066152, 61493440878115135100772134725088

Offset: 0

Author

Alois P. Heinz, Mar 05 2012

Keywords

• nonn
• walk

Comments

The first and the last letters are considered neighbors in a cyclic alphabet. The words are not considered cyclic here.

a(n) is also the number of (6*n-1)-step walks on 6-dimensional cubic lattice from (1,0,...,0) to (n,n,...,n) with positive unit steps in all dimensions such that the indices of dimensions used in consecutive steps differ by less than 2 or are in the set {1,6}.

Crossrefs

Column k=6 of A208879.