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A110593
a(1) = 3, a(n+1) = 2*(3^n).
5
3, 6, 18, 54, 162, 486, 1458, 4374, 13122, 39366, 118098, 354294, 1062882, 3188646, 9565938, 28697814, 86093442, 258280326, 774840978, 2324522934, 6973568802, 20920706406, 62762119218, 188286357654, 564859072962, 1694577218886
OFFSET
1,1
COMMENTS
Same as A025192 for n > 1. - Georg Fischer, Oct 21 2018
FORMULA
a(n) = A008776(n-1) for n>1. - R. J. Mathar, Apr 24 2007
G.f.: 3*x + 6*x^2/(1-3*x). - R. J. Mathar, Nov 18 2007
MATHEMATICA
Rest[CoefficientList[Series[3 x + 6 x^2/(1 - 3 x), {x, 0, 50}], x]] (* G. C. Greubel, Sep 01 2017 *)
Join[{3}, NestList[3#&, 6, 30]] (* Harvey P. Dale, Aug 14 2024 *)
PROG
(PARI) x='x+O('x^50); Vec(3*x + 6*x^2/(1-3*x)) \\ G. C. Greubel, Sep 01 2017
CROSSREFS
KEYWORD
easy,less,nonn
AUTHOR
Jonathan Vos Post, Jul 29 2005
STATUS
approved