A108732 a(0)=22; if n odd, a(n) = a(n-1)/2, otherwise a(n) = 4*a(n-1).

22, 11, 44, 22, 88, 44, 176, 88, 352, 176, 704, 352, 1408, 704, 2816, 1408, 5632, 2816, 11264, 5632, 22528, 11264, 45056, 22528, 90112, 45056, 180224, 90112, 360448, 180224, 720896, 360448, 1441792, 720896

Offset

0,1

Comments

A108213 is a subsequence of this sequence and is also twice this sequence.

Links

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

Index entries for linear recurrences with constant coefficients, signature (0,2)

Formula

a(2n+1) = a(2n-2).

Recurrence: a(n) = 2a(n-2), a(0)=22, a(1)=11. G.f.: (22x+44)/(1-2x^2). - Ralf Stephan, Jul 16 2013

a(n) = 11 * 2^A028242(n). - Franklin T. Adams-Watters, Mar 29 2006

Mathematica

nxt[{n_, a_}]:={n+1, If[EvenQ[n], a/2, 4a]}; NestList[nxt, {0, 22}, 40][[All, 2]] (* or *) LinearRecurrence[{0, 2}, {22, 11}, 40] (* Harvey P. Dale, Jul 22 2021 *)

Crossrefs

Cf. A005015, A108213.

Sequence in context: A033342 A102612 A040465 * A033967 A262244 A140872

Adjacent sequences: A108729 A108730 A108731 * A108733 A108734 A108735

Keyword

easy,nonn

Author

Alexandre Wajnberg & Guadalupe Garcia, Jun 22 2005

Status

approved