cp's OEIS Frontend

A209183 Number of words, either empty or beginning with the first letter of the cyclic 4-ary alphabet, where each letter of the alphabet occurs n times and letters of neighboring word positions are equal or neighbors in the alphabet.

%I A209183 #6 Mar 30 2012 17:37:37
%S A209183 1,2,62,2830,151686,8893482,552309938,35702836038,2377145582550,
%T A209183 161906392007554,11227409430866262,790011772823243214,
%U A209183 56264746328351077194,4048156319577916177530,293797748889879887735802,21483000387938509658756790,1581177100760460768472276086
%N A209183 Number of words, either empty or beginning with the first letter of the cyclic 4-ary alphabet, where each letter of the alphabet occurs n times and letters of neighboring word positions are equal or neighbors in the alphabet.
%C A209183 The first and the last letters are considered neighbors in a cyclic alphabet.  The words are not considered cyclic here.
%C A209183 a(n) is also the number of (4*n-1)-step walks on 4-dimensional cubic lattice from (1,0,0,0) to (n,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 {1,4}.
%Y A209183 Column k=4 of A208879.
%K A209183 nonn,walk
%O A209183 0,2
%A A209183 _Alois P. Heinz_, Mar 05 2012