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A293049 Expansion of e.g.f. exp(x^3/(1 - x)). 6

%I #36 Mar 15 2023 12:40:08

%S 1,0,0,6,24,120,1080,10080,100800,1149120,14515200,199584000,

%T 2973801600,47740492800,820928908800,15049152518400,292919058432000,

%U 6031865968128000,130990787582054400,2991455760887193600,71659101232502784000,1796424431562528768000

%N Expansion of e.g.f. exp(x^3/(1 - x)).

%C For n > 4, a(n) is a multiple of 10. - _Muniru A Asiru_, Oct 09 2017

%H Seiichi Manyama, <a href="/A293049/b293049.txt">Table of n, a(n) for n = 0..444</a>

%F E.g.f.: Product_{i>2} exp(x^i).

%F a(n) ~ n^(n-1/4) * exp(-5/2 + 2*sqrt(n) - n) / sqrt(2). - _Vaclav Kotesovec_, Sep 30 2017

%F a(n) = 2*(n-1) * a(n-1) - (n-1)*(n-2) * a(n-2) + 6*binomial(n-1,2) * a(n-3) - 12*binomial(n-1,3) * a(n-4) for n > 3. - _Seiichi Manyama_, Mar 15 2023

%p a:= proc(n) option remember; `if`(n=0, 1, add(

%p a(n-j)*binomial(n-1, j-1)*j!, j=3..n))

%p end:

%p seq(a(n), n=0..25); # _Alois P. Heinz_, Sep 30 2017

%p seq(factorial(k)*coeftayl(exp(x^3/(1-x)), x = 0, k),k=0..50); # _Muniru A Asiru_, Oct 09 2017

%t CoefficientList[Series[E^(x^3/(1-x)), {x, 0, 20}], x] * Range[0, 20]! (* _Vaclav Kotesovec_, Sep 30 2017 *)

%o (PARI) x='x+O('x^66); Vec(serlaplace(exp(x^3/(1-x))))

%Y Column k=2 of A293053.

%Y E.g.f.: Product_{i>k} exp(x^i): A000262 (k=0), A052845 (k=1), this sequence (k=2), A293050 (k=3).

%K nonn

%O 0,4

%A _Seiichi Manyama_, Sep 29 2017

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Last modified April 24 00:30 EDT 2024. Contains 371917 sequences. (Running on oeis4.)