A102653 a(n) = 4 * floor(9*2^n/5).

4, 12, 28, 56, 112, 228, 460, 920, 1840, 3684, 7372, 14744, 29488, 58980, 117964, 235928, 471856, 943716, 1887436, 3774872, 7549744, 15099492, 30198988, 60397976, 120795952, 241591908, 483183820, 966367640, 1932735280, 3865470564, 7730941132, 15461882264

Offset: 0

Author

Odimar Fabeny, Feb 02 2005

Keywords

• easy
• nonn
• less

Comments

In binary, each term differs from the previous by a single bit.

Links

• Index entries for linear recurrences with constant coefficients, signature (3,-3,3,-2).

Crossrefs

Cf. A102650, A102651, A102652.

Programs

Mathematica

Table[4Floor[(27 2^n)/15],{n,0,30}] (* or *) LinearRecurrence[ {3,-3,3,-2}, {4,12,28,56},30] (* Harvey P. Dale, Jun 15 2011 *)

PARI

a(n)=27<Charles R Greathouse IV, Feb 04 2016

Formula

From R. J. Mathar, Feb 20 2011: (Start)

a(n) = 4 * A151754(n+1).

G.f.: 4 * ( 1+x^2-x^3 ) / ( (x-1)*(2*x-1)*(x^2+1) ). (End)

a(0)=4, a(1)=12, a(2)=28, a(3)=56, a(n) = 3*a(n-1)-3*a(n-2)+3*a(n-3)-2*a(n-4). - Harvey P. Dale, Jun 15 2011

Extensions

Edited by Don Reble, Mar 28 2006