login
This site is supported by donations to The OEIS Foundation.

 

Logo

Annual Appeal: Today, Nov 11 2014, is the 4th anniversary of the launch of the new OEIS web site. 70,000 sequences have been added in these four years, all edited by volunteers. Please make a donation (tax deductible in the US) to help keep the OEIS running.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A052786 A simple grammar. 0
0, 0, 0, 0, 0, 0, 720, 7560, 70560, 680400, 7015680, 78004080, 935542080, 12074119200, 167122859904, 2472036446880, 38940240568320, 651087633530880, 11519998092877824, 215088381671892480 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,7

LINKS

Table of n, a(n) for n=0..19.

INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 743

FORMULA

E.g.f.: x^3*ln(-1/(-1+x))^3

Recurrence: {a(1)=0, a(2)=0, a(4)=0, a(3)=0, a(5)=0, a(6)=720, (16*n^4+135*n+162-81*n^2-42*n^3-n^6+3*n^5)*a(n)+(-228+81*n^2+3*n^5+104*n-38*n^3-6*n^4)*a(n+1)+(36+6*n^3-3*n^4+21*n^2-60*n)*a(n+2)+(-3*n^2+n^3+2*n)*a(n+3)}

MAPLE

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

CROSSREFS

Sequence in context: A029574 A119540 A052784 * A187192 A052792 A052790

Adjacent sequences:  A052783 A052784 A052785 * A052787 A052788 A052789

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 | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified December 18 19:05 EST 2014. Contains 252174 sequences.