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A190877 Expansion of e.g.f. exp(x+x^5). 4

%I #19 Feb 25 2022 12:10:13

%S 1,1,1,1,1,121,721,2521,6721,15121,1844641,20013841,119845441,

%T 519072841,1816454641,223394731561,3501661887361,29675906201761,

%U 177923109591361,844925253766561,104750282797418881

%N Expansion of e.g.f. exp(x+x^5).

%H Seiichi Manyama, <a href="/A190877/b190877.txt">Table of n, a(n) for n = 0..510</a>

%F a(n) = n! * Sum_{j=0..n/4} binomial(n+(-4)*j,j)/(n+(-4)*j)!.

%F a(n) = a(n-1) + 5! * binomial(n-1,4) * a(n-5) for n > 4. - _Seiichi Manyama_, Feb 25 2022

%t With[{nn=30},CoefficientList[Series[Exp[x+x^5],{x,0,nn}],x] Range[0,nn]!] (* _Harvey P. Dale_, Jan 25 2015 *)

%o (Maxima) a(n):=n!*sum(binomial(n+(-4)*j,j)/(n+(-4)*j)!,j,0,n/4);

%o (PARI) a(n) = if(n<5, 1, a(n-1)+5!*binomial(n-1, 4)*a(n-5)); \\ _Seiichi Manyama_, Feb 25 2022

%Y Cf. A047974, A118395, A190875.

%K nonn

%O 0,6

%A _Vladimir Kruchinin_, May 23 2011

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Last modified April 18 22:18 EDT 2024. Contains 371782 sequences. (Running on oeis4.)