login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A036068 Expansion of (-1+1/(1-3*x)^3)/(9*x). 5
1, 6, 30, 135, 567, 2268, 8748, 32805, 120285, 433026, 1535274, 5373459, 18600435, 63772920, 216827928, 731794257, 2453663097, 8178876990, 27119434230, 89494132959, 294052151151, 962352494676, 3138105960900, 10198844372925 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

G.f. for a(n)=A027472(n+3), n >= 0, is 1/(1-3*x)^3.

LINKS

Table of n, a(n) for n=0..23.

W. Lang, On generalizations of Stirling number triangles, J. Integer Seqs., Vol. 3 (2000), #00.2.4.

FORMULA

a(n) = 3^(n-1)*binomial(n+3, 2); G.f.: (-1+(1-3*x)^(-3))/(x*3^2)=(1-3*x+3*x^2)/(1-3*x)^3.

G.f.: F(4,1;2;3x); [From Paul Barry, Sep 03 2008]

D-finite with recurrence: (n+1)*a(n) +3*(-n-3)*a(n-1)=0. - R. J. Mathar, Jan 28 2020

MATHEMATICA

CoefficientList[Series[((1/(1-3x))^3-1)/(9x), {x, 0, 30}], x] (* Harvey P. Dale, Nov 26 2018 *)

CROSSREFS

Cf. A001792, A027472. a(n)= A030524(n+1, 1) (first column of triangle).

Sequence in context: A232061 A247386 A317755 * A162743 A224290 A081895

Adjacent sequences:  A036065 A036066 A036067 * A036069 A036070 A036071

KEYWORD

easy,nonn

AUTHOR

Wolfdieter Lang

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 3 13:53 EDT 2020. Contains 333197 sequences. (Running on oeis4.)