A049671 a(n) = (F(n) + F(4*n))/2, where F=A000045 (the Fibonacci sequence).

0, 2, 11, 73, 495, 3385, 23188, 158912, 1089165, 7465193, 51167105, 350704411, 2403763560, 16475640166, 112925717047, 774004378265, 5305104929355, 36361730124869, 249227005940924, 1708227311455444

Offset

0,2

Links

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

Index entries for linear recurrences with constant coefficients, signature (8,-7,-6,1).

Formula

G.f.: x*(-2+5*x+x^2) / ( (x^2-7*x+1)*(x^2+x-1) ). - R. J. Mathar, Oct 26 2015

Mathematica

Table[(Fibonacci[n]+Fibonacci[4n])/2, {n, 0, 20}] (* or *) LinearRecurrence[ {8, -7, -6, 1}, {0, 2, 11, 73}, 20] (* Harvey P. Dale, Oct 22 2017 *)

Prog

(PARI) for(n=0, 30, print1((fibonacci(4*n) + fibonacci(n))/2, ", ")) \\ G. C. Greubel, Dec 02 2017
(Magma) [(Fibonacci(4*n) + Fibonacci(n))/2: n in [0..30]]; // G. C. Greubel, Dec 02 2017

Crossrefs

Sequence in context: A371518 A363389 A323842 * A074609 A299786 A335310

Adjacent sequences: A049668 A049669 A049670 * A049672 A049673 A049674

Keyword

nonn,easy

Author

Clark Kimberling

Status

approved