A209184 Number of words, either empty or beginning with the first letter of the cyclic 5-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, 114, 12622, 1754954, 276049002, 46957069166, 8432879950182, 1576025367484986, 303680854369601602, 59946832651601518874, 12067737101428788147678, 2469034689095701731579766, 512096607962969119056789578, 107455511844928367137882085286

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 (5*n-1)-step walks on 5-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 {1,5}.

Links

Table of n, a(n) for n=0..14.

Crossrefs

Column k=5 of A208879.

Sequence in context: A157068 A008271 A362575 * A356724 A065670 A105327

Adjacent sequences: A209181 A209182 A209183 * A209185 A209186 A209187

Keyword

nonn,walk

Author

Alois P. Heinz, Mar 05 2012

Status

approved