cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A089464 Hyperbinomial transform of A089461. Also the row sums of triangle A089463, which lists the coefficients for the third hyperbinomial transform.

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%I A089464 #32 Nov 16 2017 14:12:51
%S A089464 1,4,22,163,1564,18679,268714,4538209,88188280,1940666635,47744244286,
%T A089464 1299383450941,38777402351476,1259552677645903,44247546748659130,
%U A089464 1671904534990870369,67624237153933934704,2915628368081840175379,133499617770334938670198
%N A089464 Hyperbinomial transform of A089461. Also the row sums of triangle A089463, which lists the coefficients for the third hyperbinomial transform.
%C A089464 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
%H A089464 Alois P. Heinz, <a href="/A089464/b089464.txt">Table of n, a(n) for n = 0..150</a>
%F A089464 a(n) = Sum_{k=0..n} 3*(n-k+3)^(n-k-1)*C(n, k).
%F A089464 E.g.f.: exp(x)*(-LambertW(-x)/x)^3.
%F A089464 a(n) ~ 3*exp(3+exp(-1))*n^(n-1). - _Vaclav Kotesovec_, Jul 08 2013
%p A089464 a:= n-> add(3*(n-j+3)^(n-j-1)*binomial(n,j), j=0..n):
%p A089464 seq(a(n), n=0..20);  # _Alois P. Heinz_, Oct 30 2012
%t A089464 Table[Sum[3(n-k+3)^(n-k-1) Binomial[n,k],{k,0,n}],{n,0,20}] (* _Harvey P. Dale_, Dec 04 2011 *)
%t A089464 CoefficientList[Series[E^x*(-LambertW[-x]/x)^3, {x, 0, 20}], x]* Range[0, 20]! (* _Vaclav Kotesovec_, Jul 08 2013 *)
%o A089464 (PARI) x='x+O('x^50); Vec(serlaplace(exp(x)*(-lambertw(-x)/x)^3)) \\ _G. C. Greubel_, Nov 16 2017
%Y A089464 Cf. A089461, A089463 (triangle).
%Y A089464 Column k=3 of A144303.
%K A089464 nonn
%O A089464 0,2
%A A089464 _Paul D. Hanna_, Nov 05 2003