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A213863 Number of words w where each letter of the n-ary alphabet occurs 3 times and for every prefix z of w we have #(z,a_i) = 0 or #(z,a_i) >= #(z,a_j) for all j>i and #(z,a_i) counts the occurrences of the i-th letter in z. 1
1, 1, 7, 106, 2575, 87595, 3864040, 210455470, 13681123135, 1035588754375, 89575852312675, 8724157965777400, 945424197750836500, 112891958206958894500, 14733016566584898017500, 2086947723639167040631750, 318968341048949169038143375 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..16.

EXAMPLE

a(0) = 1: the empty word.

a(1) = 1: aaa.

a(2) = 7: aaabbb, aababb, aabbab, abaabb, ababab, baaabb, baabab.

CROSSREFS

Row n=3 of A213275.

Sequence in context: A145167 A141358 A141362 * A231899 A188407 A075021

Adjacent sequences:  A213860 A213861 A213862 * A213864 A213865 A213866

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Jun 23 2012

STATUS

approved

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Last modified June 19 17:16 EDT 2019. Contains 324222 sequences. (Running on oeis4.)