A116415 a(n) = 5*a(n-1) - 3*a(n-2).

1, 5, 22, 95, 409, 1760, 7573, 32585, 140206, 603275, 2595757, 11168960, 48057529, 206780765, 889731238, 3828313895, 16472375761, 70876937120, 304967558317, 1312206980225, 5646132226174, 24294040190195, 104531804272453

Offset

0,2

Comments

Row sums of A116414.

Binomial transform of the sequence A006190. - Sergio Falcon, Nov 23 2007

a(n+1) equals the number of words of length n over {0,1,2,3,4} avoiding 01, 02 and 03. - Milan Janjic, Dec 17 2015

Links

Harvey P. Dale, Table of n, a(n) for n = 0..1000

Sergio Falcón, Iterated Binomial Transforms of the k-Fibonacci Sequence, British Journal of Mathematics & Computer Science, 4 (22): 2014.

Sergio Falcón and Ángel Plaza, On k-Fibonacci sequences and polynomials and their derivatives, Chaos, Solitons & Fractals, Volume 39, Issue 3, 15 February 2009, Pages 1005-1019.

Index entries for linear recurrences with constant coefficients, signature (5,-3).

Formula

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

a(n) = Sum_{k=0..n} Sum_{j=0..n} C(n-j,k)*C(k+j,j)*3^j.

a(n) = (1/sqrt(13))*(((5+sqrt(13))/2)^n - ((5-sqrt(13))/2)^n). - Sergio Falcon, Nov 23 2007

If p[i] = (3^i-1)/2, and if A is the Hessenberg matrix of order n defined by: A[i,j] = p[j-i+1], (i <= j), A[i,j] = -1, (i = j+1), and A[i,j] = 0 otherwise. Then, for n >= 1, a(n-1) = det(A). - Milan Janjic, May 08 2010

a(n) = 4*a(n-1) + a(n-2) + a(n-3) + ... + a(0) + 1. These expansions with the partial sums on one side can be generated en masse by taking the g.f. of the partial sum and its partial fraction, 1/(1-x)/(1 - 5*x + 3*x^2) = -1/(1-x)+(2-3*x)/(1 - 5*x + 3*x^2) and reading this as a(0) + a(1) + ... + a(n) = -1 + 2*a(n)- 3*a(n-1). - Gary W. Adamson, Feb 18 2011

Mathematica

Join[{a=1, b=5}, Table[c=5*b-3*a; a=b; b=c, {n, 60}]] (* Vladimir Joseph Stephan Orlovsky, Jan 18 2011 *)
LinearRecurrence[{5, -3}, {1, 5}, 40] (* Harvey P. Dale, Jun 19 2012 *)

Prog

(Sage) [lucas_number1(n, 5, 3) for n in range(1, 24)] # Zerinvary Lajos, Apr 22 2009
(Magma) I:=[1, 5]; [n le 2 select I[n] else 5*Self(n-1)-3*Self(n-2): n in [1..30]]; // Vincenzo Librandi, Dec 16 2015
(PARI) Vec(1/(1-5*x+3*x^2) + O(x^100)) \\ Altug Alkan, Dec 17 2015

Crossrefs

Cf. A001906, A007070, A084326.

Sequence in context: A053154 A141222 A127360 * A026861 A026888 A266430

Adjacent sequences: A116412 A116413 A116414 * A116416 A116417 A116418

Keyword

easy,nonn

Author

Paul Barry, Feb 13 2006

Status

approved