A291779 a(n) = 2^n - 2^floor(2n/3).

0, 1, 2, 4, 12, 24, 48, 112, 224, 448, 960, 1920, 3840, 7936, 15872, 31744, 64512, 129024, 258048, 520192, 1040384, 2080768, 4177920, 8355840, 16711680, 33488896, 66977792, 133955584, 268173312, 536346624, 1072693248, 2146435072, 4292870144, 8585740288, 17175674880, 34351349760, 68702699520

Offset: 0

Author

Don Reble and N. J. A. Sloane, Sep 01 2017

Keywords

• nonn

Links

• Robert Israel, Table of n, a(n) for n = 0..3318
• Index entries for linear recurrences with constant coefficients, signature (2,0,4,-8).

Crossrefs

Cf. A004523, A291778.

Programs

Maple

seq(2^n-2^floor(2*n/3),n=0..50); # Robert Israel, Sep 01 2017

Mathematica

LinearRecurrence[{2, 0, 4, -8}, {0, 1, 2, 4}, 37] (* Jean-François Alcover, Apr 02 2019 *)

Formula

G.f.: x/((1-2*x)*(1-4*x^3)). - Robert Israel, Sep 01 2017