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

1, 5, 42, 510, 8184, 163800, 3931920, 110098800, 3523201920, 126835632000, 5073428908800, 223230911904000, 10715084250393600, 557184387247488000, 31202325773037619200, 1872139547689931520000, 119816931073078407168000

Offset

0,2

Links

Table of n, a(n) for n=0..16.

INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 601

Formula

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

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}

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

a(n) = n!*A002450(n+1). - R. J. Mathar, Nov 27 2011

Maple

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

Mathematica

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

Crossrefs

Sequence in context: A355786 A347015 A102693 * A108398 A370907 A239997

Adjacent sequences: A052651 A052652 A052653 * A052655 A052656 A052657

Keyword

easy,nonn

Author

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

Status

approved