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A089464
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Hyperbinomial transform of A089461. Also the row sums of triangle A089463, which lists the coefficients for the third hyperbinomial transform.
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5
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1, 4, 22, 163, 1564, 18679, 268714, 4538209, 88188280, 1940666635, 47744244286, 1299383450941, 38777402351476, 1259552677645903, 44247546748659130, 1671904534990870369, 67624237153933934704, 2915628368081840175379, 133499617770334938670198
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OFFSET
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0,2
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COMMENTS
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a(n) is also the number of subtrees of the complete graph K_{n+2} which contain 2 fixed adjacent edges (i.e. a fixed K_{1,2}). For n=2, the a(2)=4 solutions are the 4 subtrees of K_4 which contain 2 fixed adjacent edges (i.e. those 2 edges, 1 copy of K_{1,3}, and 2 copies of P_4). - Kellie J. MacPhee, Jul 25 2013
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LINKS
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FORMULA
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a(n) = Sum_{k=0..n} 3*(n-k+3)^(n-k-1)*C(n, k).
E.g.f.: exp(x)*(-LambertW(-x)/x)^3.
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MAPLE
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a:= n-> add(3*(n-j+3)^(n-j-1)*binomial(n, j), j=0..n):
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MATHEMATICA
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Table[Sum[3(n-k+3)^(n-k-1) Binomial[n, k], {k, 0, n}], {n, 0, 20}] (* Harvey P. Dale, Dec 04 2011 *)
CoefficientList[Series[E^x*(-LambertW[-x]/x)^3, {x, 0, 20}], x]* Range[0, 20]! (* Vaclav Kotesovec, Jul 08 2013 *)
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PROG
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(PARI) x='x+O('x^50); Vec(serlaplace(exp(x)*(-lambertw(-x)/x)^3)) \\ G. C. Greubel, Nov 16 2017
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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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