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A004936
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Numerator of (binomial(2*n-2,n-1)/n!)^2.
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3
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1, 1, 1, 25, 49, 49, 121, 20449, 20449, 5909761, 17631601, 17631601, 55190041, 55190041, 55190041, 46414824481, 154341336769, 154341336769, 427538329, 585299972401, 585299972401, 983889253606081, 3438962627443561, 3438962627443561, 7596668444022826249
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OFFSET
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1,4
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LINKS
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FORMULA
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MATHEMATICA
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Numerator[Table[(Binomial[2n-2, n-1]/n!)^2, {n, 30}]] (* Harvey P. Dale, May 30 2012 *)
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PROG
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(PARI) a(n) = numerator((binomial(2*n-2, n-1)/n!)^2); \\ Michel Marcus, Jul 14 2022
(Magma) [Numerator((Catalan(n-1)/Factorial(n-1))^2): n in [1..40]]; // G. C. Greubel, Sep 12 2023
(SageMath) [numerator((catalan_number(n-1)/factorial(n-1))^2) for n in range(1, 41)] # G. C. Greubel, Sep 12 2023
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CROSSREFS
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KEYWORD
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nonn,frac
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AUTHOR
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STATUS
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approved
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