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A278884
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a(n) = binomial(3*n-1,n) * binomial(3*n,n)/(2*n+1).
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3
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1, 2, 30, 672, 18150, 546546, 17672928, 600935040, 21212454582, 770748371250, 28657235757150, 1085694550387200, 41778588391394400, 1628982594897249312, 64234570537702934400, 2557710564063135005184, 102714012593435476016982, 4155894894567674772785250, 169274181059121504574121550, 6935873114065443534326340000, 285716428631735196825345889350, 11826871503027977442890882704050, 491714173272153004121882711232000
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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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4*n^2*(2*n-1)*(2*n+1)*a(n) -9*(3*n-1)^2*(3*n-2)^2*a(n-1)=0. - R. J. Mathar, Dec 02 2016
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MATHEMATICA
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Table[(Binomial[3n-1, n]Binomial[3n, n])/(2n+1), {n, 0, 50}] (* Harvey P. Dale, Mar 26 2023 *)
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PROG
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(PARI) {a(n) = binomial(3*n-1, n) * binomial(3*n, n) / (2*n+1)}
for(n=0, 20, print1(a(n), ", "))
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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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