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A282734
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Number of triangulations of a convex 5-gon in the plane each of whose sides is subdivided by n points.
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1
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5, 250, 13740, 699310, 33138675, 1484701075, 63681535780, 2639190848280, 106403568809545, 4194330516135610, 162275686298727710, 6180361117463387590, 232249233257266145145, 8627435520542763854065, 317285140062014506979360, 11566298576075812803892160
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OFFSET
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0,1
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LINKS
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FORMULA
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From Asinowski and Krattenthaler equation 2.7: a(n) = tr(5,n+1). - Lars Blomberg, Mar 04 2017
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MATHEMATICA
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tr[k_, r_] := Sum[(-1)^j 2^l Binomial[k, j] Binomial[k-2+l, l] Binomial[ (r-1)k-l-3, r k - (r+1)j-l-2], {j, 0, k}, {l, 0, r k - (r+1)j - 2}];
a[n_] := tr[5, n+1];
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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