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A213291 Number of n-length words w over ternary alphabet such that 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. 2
1, 3, 9, 18, 36, 74, 165, 367, 869, 2074, 5168, 13026, 33749, 88368, 235389, 632324, 1717202, 4693604, 12921864, 35751336, 99416633, 277527448, 777659128, 2185854247, 6162168724, 17416305904, 49342480077, 140094014788, 398558682310, 1135962971848 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..200

EXAMPLE

a(0) = 1: the empty word.

a(1) = 3: a, b, c for alphabet {a,b,c}.

a(2) = 9: aa, ab, ac, ba, bb, bc, ca, cb, cc.

a(3) = 18: aaa, aab, aac, aba, abc, aca, acb, baa, bac, bbb, bbc, bca, bcb, caa, cab, cba, cbb, ccc.

CROSSREFS

Column k=3 of A213276.

Sequence in context: A127645 A000241 A028723 * A264365 A291143 A057578

Adjacent sequences:  A213288 A213289 A213290 * A213292 A213293 A213294

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Jun 08 2012

STATUS

approved

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Last modified October 16 20:23 EDT 2019. Contains 328103 sequences. (Running on oeis4.)