A155543 a(n)=2*A081294(n).

2, 4, 16, 64, 256, 1024, 4096, 16384, 65536, 262144, 1048576, 4194304, 16777216, 67108864, 268435456, 1073741824, 4294967296, 17179869184, 68719476736, 274877906944, 1099511627776, 4398046511104, 17592186044416, 70368744177664

Offset

0,1

Links

Table of n, a(n) for n=0..23.

Index entries for linear recurrences with constant coefficients, signature (4).

Formula

a(n)=A000302(n), n>0.

G.f.: 2*(1-2*x)/(1-4*x). [R. J. Mathar, Jul 23 2009]

Conjecture: a(n)=A090129(2n+2).

Mathematica

CoefficientList[Series[2(1-2x)/(1-4x), {x, 0, 30}], x] (* or *) Join[{2}, NestList[ 4#&, 4, 30]] (* Harvey P. Dale, Nov 13 2015 *)

Crossrefs

Sequence in context: A187822 A092585 A106186 * A151371 A001900 A113247

Adjacent sequences: A155540 A155541 A155542 * A155544 A155545 A155546

Keyword

nonn,easy

Author

Paul Curtz, Jan 24 2009

Extensions

Edited and extended by R. J. Mathar, Jul 23 2009

Status

approved