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A370057
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a(n) = 3*(4*n+2)!/(3*n+3)!.
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3
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1, 3, 30, 546, 14688, 526680, 23680800, 1282554000, 81339793920, 5915366392320, 485415660038400, 44376781223174400, 4473125162795520000, 492902545595556096000, 58949616073242166272000, 7605168496387089788160000, 1052810955815818170875904000
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OFFSET
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0,2
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LINKS
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FORMULA
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E.g.f.: exp( 3/4 * Sum_{k>=1} binomial(4*k,k) * x^k/k ).
D-finite with recurrence 3*(3*n+2)*(3*n+1)*(n+1)*a(n) -8*n*(4*n+1)*(2*n+1)*(4*n-1)*a(n-1)=0. - R. J. Mathar, Feb 22 2024
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PROG
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(PARI) a(n) = 3*(4*n+2)!/(3*n+3)!;
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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