The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A109438 a(n) = 5a(n-1) - 5a(n-2) + a(n-3) + 2*(-1)^(n+1), alternatively a(n) = 3a(n-1) + 3a(n-2) - a(n-3). 2
 1, 5, 18, 68, 253, 945, 3526, 13160, 49113, 183293, 684058, 2552940, 9527701, 35557865, 132703758, 495257168, 1848324913, 6898042485, 25743845026, 96077337620, 358565505453, 1338184684193, 4994173231318, 18638508241080 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS See A109437 for comments. Floretion Algebra Multiplication Program, FAMP Code: (-1)^(n)jbasejfor[ + .5'ii' + .5'kk' + .5'ij' + .5'ji' + .5'jk' + .5'kj'] 1vesfor = (-1,-1,-1,-1,) LINKS Colin Barker, Table of n, a(n) for n = 0..1000 Index entries for linear recurrences with constant coefficients, signature (3,3,-1). FORMULA G.f.: (1+2*x) / ((x+1)*(x^2-4*x+1)). a(n) = (-2*(-1)^n + (7-5*sqrt(3))*(2-sqrt(3))^n + (2+sqrt(3))^n*(7+5*sqrt(3))) / 12. - Colin Barker, May 12 2019 MATHEMATICA LinearRecurrence[{3, 3, -1}, {1, 5, 18}, 30] (* Harvey P. Dale, Sep 07 2021 *) PROG (PARI) Vec((1 + 2*x) / ((1 + x)*(1 - 4*x + x^2)) + O(x^30)) \\ Colin Barker, May 12 2019 CROSSREFS Cf. A109437, A001834, A102871. Sequence in context: A322497 A279488 A199843 * A164051 A134764 A188177 Adjacent sequences: A109435 A109436 A109437 * A109439 A109440 A109441 KEYWORD easy,nonn AUTHOR Creighton Dement, Jun 28 2005 STATUS approved

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

Last modified April 21 19:32 EDT 2024. Contains 371885 sequences. (Running on oeis4.)