# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a109438 Showing 1-1 of 1 %I A109438 #14 Mar 12 2024 12:16:39 %S A109438 1,5,18,68,253,945,3526,13160,49113,183293,684058,2552940,9527701, %T A109438 35557865,132703758,495257168,1848324913,6898042485,25743845026, %U A109438 96077337620,358565505453,1338184684193,4994173231318,18638508241080 %N 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). %C A109438 See A109437 for comments. %C A109438 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,) %H A109438 Colin Barker, Table of n, a(n) for n = 0..1000 %H A109438 Index entries for linear recurrences with constant coefficients, signature (3,3,-1). %F A109438 G.f.: (1+2*x) / ((x+1)*(x^2-4*x+1)). %F A109438 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 %t A109438 LinearRecurrence[{3,3,-1},{1,5,18},30] (* _Harvey P. Dale_, Sep 07 2021 *) %o A109438 (PARI) Vec((1 + 2*x) / ((1 + x)*(1 - 4*x + x^2)) + O(x^30)) \\ _Colin Barker_, May 12 2019 %Y A109438 Cf. A109437, A001834, A102871. %K A109438 easy,nonn %O A109438 0,2 %A A109438 _Creighton Dement_, Jun 28 2005 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE