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!)
A092803 Expansion of (1-5x)/((1-2x)(1-6x)). 1
1, 3, 12, 60, 336, 1968, 11712, 70080, 420096, 2519808, 15117312, 90700800, 544198656, 3265179648, 19591053312, 117546270720, 705277526016, 4231664959488, 25389989363712, 152339935395840, 914039610802176 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Second binomial transform of expansion of (1-3x)/(1-4x). Third binomial transform of A054878 (closed walks at a vertex of K_4). With interpolated zeros, counts closed walks of length n at the vertices of the edge-vertex incidence graph of K_4 associated with the vertices of K_4.

LINKS

Table of n, a(n) for n=0..20.

Index entries for linear recurrences with constant coefficients, signature (8,-12).

FORMULA

a(n)=2^(n-2)(3^n+3)=(6^n+3*2^n)/4

G.f.: U(0)/4 where U(k)= 1 + 2/(3^k - 3^k/(2 + 1 - 12*x*3^k/(6*x*3^k + 1/U(k+1)))) ; (continued fraction, 4-step). - Sergei N. Gladkovskii, Oct 30 2012

G.f.: U(0)/4 where U(k)= 1 + 3/( 3^k - 2*x*9^k/(2*x*3^k + 1/U(k+1))) ; (continued fraction, 3-step). - Sergei N. Gladkovskii, Oct 31 2012

CROSSREFS

Sequence in context: A003483 A278395 A128602 * A181282 A020052 A096471

Adjacent sequences:  A092800 A092801 A092802 * A092804 A092805 A092806

KEYWORD

easy,nonn

AUTHOR

Paul Barry, Mar 06 2004

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 February 26 14:39 EST 2021. Contains 341632 sequences. (Running on oeis4.)