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A113078 Number of tournament sequences: a(n) gives the number of n-th generation descendents of a node labeled (4) in the tree of tournament sequences. 11
1, 4, 26, 274, 4721, 134899, 6501536, 537766009, 77598500096, 19821981700354, 9077118324755246, 7531446638893873684, 11423775838657143826346, 31914367054676982206368909, 165251261153335414813452988541 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Equals column 4 of square table A093729. Also equals column 0 of the matrix 4-th power of triangle A097710, which satisfies the matrix recurrence: A097710(n,k) = [A097710^2](n-1,k-1) + [A097710^2](n-1,k) for n>k>=0.

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 tournament sequences of descendents of

a node labeled (4) begins:

[4]; generation 1: 4->[5,6,7,8]; generation 2: 5->[6,7,8,9,10],

6->[7,8,9,10,11,12], 7->[8,9,10,11,12,13,14],

8->[9,10,11,12,13,14,15,16]; ...

Then a(n) gives the number of nodes in generation n.

Also, a(n+1) = sum of labels of nodes in generation n.

PROG

(PARI) {a(n, q=2)=local(M=matrix(n+1, n+1)); for(r=1, n+1, for(c=1, r, M[r, c]=if(r==c, 1, if(c>1, (M^q)[r-1, c-1])+(M^q)[r-1, c]))); return((M^4)[n+1, 1])}

CROSSREFS

Cf. A113077, A113079, A008934, A113089, A113096, A113098, A113100, A113107, A113109, A113111, A113113.

Sequence in context: A002465 A079473 A145164 * A177451 A167811 A156306

Adjacent sequences:  A113075 A113076 A113077 * A113079 A113080 A113081

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Oct 14 2005

STATUS

approved

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Last modified May 21 10:43 EDT 2013. Contains 225478 sequences.