A113085 - OEIS

A113085

Number of 3-tournament sequences: a(n) gives the number of increasing sequences of n positive integers (t_1,t_2,...,t_n) such that t_1 = 1 and t_i = 1 (mod 2) and t_{i+1} <= 3*t_i for 1<i<n.

1, 1, 3, 21, 331, 11973, 1030091, 218626341, 118038692523, 166013096151621, 619176055256353291, 6207997057962300681573, 169117528577725378851523691, 12626174170113987651028630856581, 2602022118010488151483064379958957003

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OFFSET

0,3

COMMENTS

Equals column 0 of triangle A113084, which satisfies: A113084(n,k) = [A113084^3](n-1,k-1) + [A113084^3](n-1,k).

LINKS

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

M. Cook and M. Kleber, Tournament sequences and Meeussen sequences, Electronic J. Comb. 7 (2000), #R44.

EXAMPLE

The tree of 3-tournament sequences of odd integer

descendents of a node labeled (1) begins:

[1]; generation 1: 1->[3]; generation 2: 3->[5,7,9];