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!)
A074582 a(n) = S(3n), where S(n) is the generalized tribonacci sequence A001644. 1
3, 7, 39, 241, 1499, 9327, 58035, 361109, 2246915, 13980895, 86992799, 541292033, 3368061131, 20956960551, 130399710235, 811381230021, 5048627019523, 31413882696791, 195465425009943, 1216237188605169, 7567747077883259 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (7,-5,1).

FORMULA

a(n) = 7*a(n-1) - 5*a(n-2) + a(n-3), a(0)=3, a(1)=7, a(2)=39.

G.f.: (3-14*x+5*x^2)/(1-7*x+5*x^2-x^3).

MATHEMATICA

CoefficientList[Series[(3-14*x+5*x^2)/(1-7*x+5*x^2-x^3), {x, 0, 30}], x]

PROG

(PARI) my(x='x+O('x^30)); Vec((3-14*x+5*x^2)/(1-7*x+5*x^2-x^3)) \\ G. C. Greubel, Apr 13 2019

(MAGMA) R<x>:=PowerSeriesRing(Integers(), 30); Coefficients(R!( (3-14*x+5*x^2)/(1-7*x+5*x^2-x^3) )); // G. C. Greubel, Apr 13 2019

(Sage) ((3-14*x+5*x^2)/(1-7*x+5*x^2-x^3)).series(x, 30).coefficients(x, sparse=False) # G. C. Greubel, Apr 13 2019

CROSSREFS

Cf. A001644, A074581.

Sequence in context: A113870 A209326 A307952 * A105621 A181081 A166895

Adjacent sequences:  A074579 A074580 A074581 * A074583 A074584 A074585

KEYWORD

easy,nonn

AUTHOR

Mario Catalani (mario.catalani(AT)unito.it), Aug 24 2002

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 4 05:34 EDT 2020. Contains 333212 sequences. (Running on oeis4.)