A110594 a(1) = 4, a(2) = 12, for n>1: a(n) = 3*4^(n-1).

4, 12, 48, 192, 768, 3072, 12288, 49152, 196608, 786432, 3145728, 12582912, 50331648, 201326592, 805306368, 3221225472, 12884901888, 51539607552, 206158430208, 824633720832, 3298534883328, 13194139533312, 52776558133248

Offset: 1

Author

Jonathan Vos Post, Jul 29 2005

Keywords

• easy
• less
• nonn

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000
• Index entries for linear recurrences with constant coefficients, signature (4).

Crossrefs

Cf. A000302, A007090, A081604, A110591, A110593.

Programs

GAP

Concatenation([4],List([2..25],n->3*4^(n-1))); # Muniru A Asiru, Oct 21 2018

Magma

[4] cat [3*4^(n-1): n in [2..30]]; // Vincenzo Librandi, May 29 2014

Maple

seq(coeff(series(4*x*(1-x)/(1-4*x),x,n+1), x, n), n = 1 .. 25); # Muniru A Asiru, Oct 21 2018

Mathematica

CoefficientList[Series[4 (1 - x)/(1 - 4 x), {x, 0, 40}], x] (* Vincenzo Librandi, May 29 2014 *)

PARI

x='x+O('x^50); Vec(4*x*(1 - x)/(1 - 4*x)) \\ G. C. Greubel, Sep 01 2017

Formula

a(n) = A002001(n), n>1. - R. J. Mathar, Aug 18 2008

G.f.: 4*x*(1 - x)/(1 - 4*x). - Vincenzo Librandi, May 29 2014

Extensions

Definition corrected by R. J. Mathar, Aug 18 2008