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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
OFFSET
1,1
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
KEYWORD
easy,less,nonn
AUTHOR
Jonathan Vos Post, Jul 29 2005
EXTENSIONS
Definition corrected by R. J. Mathar, Aug 18 2008
STATUS
approved