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A013780
a(n) = 4^(4*n + 1).
2
4, 1024, 262144, 67108864, 17179869184, 4398046511104, 1125899906842624, 288230376151711744, 73786976294838206464, 18889465931478580854784, 4835703278458516698824704, 1237940039285380274899124224
OFFSET
0,1
FORMULA
From Philippe Deléham, Nov 27 2008: (Start)
a(n) = 256*a(n-1); a(0)=4.
G.f.: 4/(1-256*x). (End)
MATHEMATICA
NestList[256#&, 4, 20] (* Harvey P. Dale, Aug 09 2013 *)
PROG
(Magma) [4^(4*n+1): n in [0..15]]; // Vincenzo Librandi, Jun 17 2011
(PARI) a(n)=4^(4*n+1) \\ Charles R Greathouse IV, Jul 11 2016
CROSSREFS
Sequence in context: A069920 A368371 A217024 * A139300 A004804 A221228
KEYWORD
nonn,easy
STATUS
approved