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A110594 a(1) = 4, a(2) = 12, for n>1: a(n) = 3*4^(n-1). 6
4, 12, 48, 192, 768, 3072, 12288, 49152, 196608, 786432, 3145728, 12582912, 50331648, 201326592, 805306368, 3221225472, 12884901888, 51539607552, 206158430208, 824633720832, 3298534883328, 13194139533312, 52776558133248 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

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

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 *)

PROG

(MAGMA) [4] cat [3*4^(n-1): n in [2..30]]; // 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

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

CROSSREFS

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

Sequence in context: A056632 A149385 A092898 * A151483 A192622 A324801

Adjacent sequences:  A110591 A110592 A110593 * A110595 A110596 A110597

KEYWORD

easy,less,nonn

AUTHOR

Jonathan Vos Post, Jul 29 2005

EXTENSIONS

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

STATUS

approved

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Last modified February 20 04:25 EST 2020. Contains 332063 sequences. (Running on oeis4.)