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A065424
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Catalan-like formula: a(n) = binomial(6*n, 3*n+1)/(9*n+6).
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1
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1, 33, 1326, 59432, 2851425, 143291610, 7446255180, 396893583792, 21579377870484, 1192183281903845, 66734212415276406, 3776778437640143208, 215744630060724034270, 12423227699242323077940
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OFFSET
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1,2
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LINKS
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FORMULA
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G.f.: A*sqrt((A+1)*(1+9*A)) where A=x*(1+9*A)^3*(1+A). - Mark van Hoeij, Nov 16 2011
-(n-1)*(3*n+2)*(3*n+1)*a(n) + 8*(6*n-5)*(6*n-1)*(2*n-1)*a(n-1) = 0. - R. J. Mathar, Oct 31 2015
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PROG
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(Magma) [Binomial(6*n, 3*n+1)/(9*n+6): n in [1..20]]; // Vincenzo Librandi, Nov 17 2011
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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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STATUS
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approved
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