

A209185


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


1



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

0,2


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*n1)step walks on 6dimensional 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}.


LINKS



CROSSREFS



KEYWORD

nonn,walk


AUTHOR



STATUS

approved



