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A140136 Numerator coefficients for generators of lattice path enumeration square array A111910. +0
1
1, 1, 1, 1, 7, 7, 1, 1, 20, 75, 75, 20, 1, 1, 42, 364, 1001, 1001, 364, 42, 1, 1, 75, 1212, 6720, 15288, 15288, 6720, 1212, 75, 1, 1, 121, 3223, 30723, 127908, 255816, 255816, 127908, 30723, 3223, 121, 1, 1, 182, 7371, 109538, 737737, 2510508 (list; graph; listen)
OFFSET

0,5

COMMENT

sum{k=0..n, T(n,k)x^k}/(1-x)^(3n+1) generates row n of A111910.

Row sums are A006335. - Paul Barry (pbarry(AT)wit.ie), May 09 2008

REFERENCES

G. Kreweras and H. Niederhausen, Solution of an enumerative problem connected with lattice paths, European J. Combin., 2 (1981), 55-60.

FORMULA

Triangle T(q,n) where T(n,q)=sum{j=0..n, (-1)^j*C(3q+1,j)*K(n-j,q)} with K(p,q)=A111910(p,q).

EXAMPLE

Triangle begins

1,

1,1,

1,7,7,1,

1,20,75,75,20,1,

1,42,364,1001,1001,364,42,1,

1,75,1212,6720,15288,15288,6720,1212,75,1

CROSSREFS

Sequence in context: A019725 A064890 A046542 this_sequence A156722 A152565 A146322

Adjacent sequences: A140133 A140134 A140135 this_sequence A140137 A140138 A140139

KEYWORD

easy,nonn

AUTHOR

Paul Barry (pbarry(AT)wit.ie), May 09 2008

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Last modified November 25 14:49 EST 2009. Contains 167514 sequences.


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