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A052654 E.g.f. 1/((1-x)(1-4x)). 0

%I #15 Apr 18 2017 07:03:58

%S 1,5,42,510,8184,163800,3931920,110098800,3523201920,126835632000,

%T 5073428908800,223230911904000,10715084250393600,557184387247488000,

%U 31202325773037619200,1872139547689931520000,119816931073078407168000

%N E.g.f. 1/((1-x)(1-4x)).

%H INRIA Algorithms Project, <a href="http://ecs.inria.fr/services/structure?nbr=601">Encyclopedia of Combinatorial Structures 601</a>

%F E.g.f.: 1/(-1+x)/(-1+4*x)

%F Recurrence: {a(0)=1, a(1)=5, (4*n^2+12*n+8)*a(n)+(-10-5*n)*a(n+1)+a(n+2)=0}

%F (-1/3+1/3*4^(n+1))*n!

%F a(n) = n!*A002450(n+1). - _R. J. Mathar_, Nov 27 2011

%p spec := [S,{S=Prod(Sequence(Z),Sequence(Union(Z,Z,Z,Z)))},labeled]: seq(combstruct[count](spec,size=n), n=0..20);

%t With[{nn=20},CoefficientList[Series[1/((1-x)(1-4x)),{x,0,nn}],x] Range[0,nn]!] (* _Harvey P. Dale_, Mar 13 2015 *)

%K easy,nonn

%O 0,2

%A encyclopedia(AT)pommard.inria.fr, Jan 25 2000

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Last modified April 20 15:37 EDT 2024. Contains 371844 sequences. (Running on oeis4.)