A105398 A simple "Fractal Jump Sequence" (FJS).

4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4

Offset

4,1

Comments

See A105397 for definition of Fractal Jump Sequence.

Continued fraction expansion of (4+3*sqrt(2))/2. - Bruno Berselli, Nov 09 2011

Period 2: repeat [4, 8]. - Wesley Ivan Hurt, Feb 12 2017

Links

Table of n, a(n) for n=4..108.

Index entries for linear recurrences with constant coefficients, signature (0,1).

Formula

G.f.: -4*x^4*(1+2*x) / ( (x-1)*(1+x) ). - R. J. Mathar, Jul 07 2011

a(n) = a(-n) = a(n-2) = 2*(3-(-1)^n) = 2^((5-(-1)^n)/2). - Bruno Berselli, Nov 09 2011

Maple

A105398:=n->2*(3-(-1)^n): seq(A105398(n), n=0..150); # Wesley Ivan Hurt, Feb 12 2017

Mathematica

PadRight[{}, 110, {4, 8}] (* Harvey P. Dale, Nov 09 2011 *)

Prog

(Sage) [power_mod(2, n, 12)for n in range(2, 108)] # Zerinvary Lajos, Nov 03 2009
(Maxima) makelist(if evenp(n) then 4 else 8, n, 0, 30); /* Martin Ettl, Nov 12 2012 */

Crossrefs

Cf. A105397.

Sequence in context: A155970 A348573 A010713 * A005883 A055026 A336818

Adjacent sequences: A105395 A105396 A105397 * A105399 A105400 A105401

Keyword

nonn,base,easy

Author

Eric Angelini, May 01 2005

Status

approved