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

 

Logo

The submissions stack has been unacceptably high for several months now. Please voluntarily restrict your submissions and please help with the editing. (We don't want to have to impose further limits.)

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A087452 G.f.: (2-x)/((1+3x)(1-4x)); e.g.f.: exp(4x)+exp(-3x); a(n)=4^n+(-3)^n. 1
2, 1, 25, 37, 337, 781, 4825, 14197, 72097, 242461, 1107625, 4017157, 17308657, 65514541, 273218425, 1059392917, 4338014017, 17050729021, 69106897225, 273715645477, 1102998412177, 4387586157901, 17623567104025, 70274600998837, 281757406247137 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Generalized Lucas-Jacobsthal numbers.

LINKS

Table of n, a(n) for n=0..24.

Index entries for linear recurrences with constant coefficients, signature (1,12).

FORMULA

The sequence 1, 25, 37, ... is 4*4^n-3*(-3)^n.

a(0)=2, a(1)=1, a(n)=a(n-1)+12*a(n-2) for n>1. [From Philippe Deléham, Sep 19 2009]

a(n) = 2*A053404(n) - A053404(n-1), n>0. - Ralf Stephan, Jul 21 2013

MATHEMATICA

CoefficientList[Series[(2 - z)/((1 + 3 z) (1 - 4 z)), {z, 0, 200}], z] (* Vladimir Joseph Stephan Orlovsky, Jun 11 2011 *)

PROG

(PARI) polsym(x^2-x-12, 50) \\ Charles R Greathouse IV, Jun 11 2011

CROSSREFS

Cf. A014551, A087451.

Sequence in context: A013313 A013317 A010256 * A098878 A235031 A138955

Adjacent sequences:  A087449 A087450 A087451 * A087453 A087454 A087455

KEYWORD

easy,nonn

AUTHOR

Paul Barry, Sep 06 2003

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 August 28 08:35 EDT 2015. Contains 261118 sequences.