A088313 Number of "sets of lists" (cf. A000262) with an odd number of lists.
0, 1, 2, 7, 36, 241, 1950, 18271, 193256, 2270017, 29272410, 410815351, 6231230412, 101560835377, 1769925341366, 32838929702671, 646218442877520, 13441862819232001, 294656673023216946, 6788407001443004647, 163962850573039534580, 4142654439686285737201
Offset: 0
Links
- Alois P. Heinz, Table of n, a(n) for n = 0..444
- N. Heninger, E. M. Rains and N. J. A. Sloane, On the Integrality of n-th Roots of Generating Functions, arXiv:math/0509316 [math.NT], 2005-2006; J. Combinatorial Theory, Series A, 113 (2006), 1732-1745.
- N. J. A. Sloane, LAH transform
Programs
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Magma
R
:=PowerSeriesRing(Rationals(), 30); [0] cat Coefficients(R!(Laplace( Sinh(x/(1-x)) ))); // G. C. Greubel, Dec 13 2022 -
Maple
b:= proc(n, t) option remember; `if`(n=0, t, add( b(n-j, 1-t)*binomial(n-1, j-1)*j!, j=1..n)) end: a:= n-> b(n, 0): seq(a(n), n=0..30); # Alois P. Heinz, May 10 2016 A088313 := n -> ifelse(n=0, 0, n!*hypergeom([1/2 - n/2, 1 - n/2], [1/2, 1, 3/2], 1/4)): seq(simplify(A088313(n)), n = 0..21); # Peter Luschny, Dec 14 2022
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Mathematica
With[{m=30}, CoefficientList[Series[Sinh[x/(1-x)], {x,0,m}], x] * Range[0,m]!] (* Vaclav Kotesovec, Jul 04 2015 *)
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PARI
my(x='x+O('x^66)); concat(0, Vec(serlaplace(sinh(x/(1-x))))) \\ Joerg Arndt, Jul 16 2013
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SageMath
def A088313_list(prec): P.
= PowerSeriesRing(QQ, prec) return P( sinh(x/(1-x)) ).egf_to_ogf().list() A088313_list(40) # G. C. Greubel, Dec 13 2022
Formula
E.g.f.: sinh(x/(1-x)).
a(n) = Sum_{k=1..floor((n+1)/2)} n!/(2*k-1)!*binomial(n-1, 2*k-2).
E.g.f.: sinh(x/(1-x)) = x/(2-2*x)*E(0), where E(k)= 1 + 1/( 1 - x^2/(x^2 + 2*(1-x)^2*(k+1)*(2*k+3)/E(k+1) )); (continued fraction). - Sergei N. Gladkovskii, Jul 16 2013
a(n) ~ 2^(-3/2) * n^(n-1/4) * exp(2*sqrt(n)-n-1/2). - Vaclav Kotesovec, Jul 04 2015
a(n) = n!*hypergeom([1/2 - n/2, 1 - n/2], [1/2, 1, 3/2], 1/4) for n >= 1. - Peter Luschny, Dec 14 2022
Extensions
a(0)=0 prepended by Alois P. Heinz, May 10 2016
Comments