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A006632 3*binomial(4*n-1,n-1)/(4*n-1).
(Formerly M2997)
+0
9
1, 3, 15, 91, 612, 4389, 32890, 254475, 2017356, 16301164, 133767543, 1111731933, 9338434700, 79155435870, 676196049060, 5815796869995, 50318860986108, 437662920058980, 3824609516638444, 33563127932394060, 295655735395397520, 2613391671568320765 (list; graph; listen)
OFFSET

1,2

REFERENCES

H. M. Finucan, Some decompositions of generalized Catalan numbers, pp. 275-293 of Combinatorial Mathematics IX. Proc. Ninth Australian Conference (Brisbane, August 1981). Ed. E. J. Billington, S. Oates-Williams and A. P. Street. Lecture Notes Math., 952. Springer-Verlag, 1982.

LINKS

INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 438

FORMULA

a(n) = binom[4n+3, n+1]/(4n+3) = 3 binom[4n+2, n] - binom[4n+2, n+1]. - David Callan (callan(AT)stat.wisc.edu), Sep 15 2004

MATHEMATICA

InverseSeries[Series[y*(1-y)^3, {y, 0, 24}], x] (* then A(x)=y(x)/x *) - Len Smiley Apr 07 2000

CROSSREFS

A112385 divided by 2.

Sequence in context: A077783 A047019 A099251 this_sequence A020018 A124553 A020108

Adjacent sequences: A006629 A006630 A006631 this_sequence A006633 A006634 A006635

KEYWORD

nonn

AUTHOR

Simon Plouffe (plouffe(AT)math.uqam.ca)

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Last modified July 19 08:04 EDT 2008. Contains 142098 sequences.


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