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A029609
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Central numbers in the (2,3)-Pascal triangle A029600.
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5
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1, 5, 15, 50, 175, 630, 2310, 8580, 32175, 121550, 461890, 1763580, 6760390, 26001500, 100291500, 387793800, 1502700975, 5834015550, 22687838250, 88363159500, 344616322050, 1345644686100, 5260247409300, 20583576819000
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OFFSET
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0,2
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COMMENTS
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LINKS
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FORMULA
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From Peter Bala, Aug 16 2011: (Start)
a(n) = 5/2*binomial(2*n,n) for n >= 1.
O.g.f.: -3/2+5/2*1/sqrt(1-4*x) = 1+5*x+15*x^2+50*x^3+... = 1+5*x*d/dx(log(C(x))), where C(x) is the o.g.f. for the Catalan numbers A000108. (End)
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PROG
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(Haskell)
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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