The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A052583 E.g.f. x(1-x)/(1-x-x^2). 0
 0, 1, 0, 6, 24, 240, 2160, 25200, 322560, 4717440, 76204800, 1357171200, 26345088000, 554204851200, 12553673932800, 304688127744000, 7887891787776000, 216969331138560000, 6319142847553536000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 LINKS INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 527 FORMULA E.g.f.: x*(-1+x)/(-1+x+x^2) Recurrence: {a(1)=1, a(0)=0, a(2)=0, (-2-n^2-3*n)*a(n)+(-2-n)*a(n+1)+a(n+2)=0} Sum(-1/5*(-3+4*_alpha)*_alpha^(-1-n), _alpha=RootOf(-1+_Z+_Z^2))*n! a(n)=n!*A212804(n-1). - R. J. Mathar, Jun 03 2022 MAPLE spec := [S, {S=Prod(Z, Sequence(Prod(Z, Z, Sequence(Z))))}, labeled]: seq(combstruct[count](spec, size=n), n=0..20); MATHEMATICA With[{nn=20}, CoefficientList[Series[x (1-x)/(1-x-x^2), {x, 0, nn}], x]Range[0, nn]!] (* Harvey P. Dale, Jul 24 2012 *) CROSSREFS Sequence in context: A231317 A223105 A112675 * A052671 A052733 A323449 Adjacent sequences:  A052580 A052581 A052582 * A052584 A052585 A052586 KEYWORD easy,nonn AUTHOR encyclopedia(AT)pommard.inria.fr, Jan 25 2000 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified July 1 19:49 EDT 2022. Contains 354974 sequences. (Running on oeis4.)