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A097476
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a(n) = Product_{i=0..n-1} ((2i)!)^2.
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1
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OFFSET
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1,2
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COMMENTS
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a(n) = determinant of n X n matrix m(i,j)=E(2i+2j), 0<=i,j<=n-1, where E(2k) is the (2k)-th signless Euler number in 1/cos(z) = Sum_{k>=0} E(2k)*z^(2k)/(2k)!.
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REFERENCES
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C. Krattenthaler, Advanced Determinant Calculus, p. 46
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LINKS
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Table of n, a(n) for n=1..7.
C. Krattenthaler, Advanced Determinant Calculus, Séminaire Lotharingien Combin. 42 ("The Andrews Festschrift") (1999), Article B42q, 67 pp.
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MATHEMATICA
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Table[Product[((2i)!)^2, {i, 0, n-1}], {n, 8}] (* Harvey P. Dale, Jul 05 2021 *)
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PROG
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(PARI) a(n)=prod(i=0, n-1, ((2*i)!)^2)
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CROSSREFS
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Sequence in context: A062407 A212799 A343695 * A047676 A280790 A079187
Adjacent sequences: A097473 A097474 A097475 * A097477 A097478 A097479
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KEYWORD
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nonn
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AUTHOR
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Benoit Cloitre, Sep 18 2004
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STATUS
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approved
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