A182465 a(n) = 3a(n-1) - 2a(n-2) with a(0)=28 and a(1)=70.

28, 70, 154, 322, 658, 1330, 2674, 5362, 10738, 21490, 42994, 86002, 172018, 344050, 688114, 1376242, 2752498, 5505010, 11010034, 22020082, 44040178, 88080370, 176160754, 352321522, 704643058, 1409286130, 2818572274, 5637144562, 11274289138, 22548578290

Offset: 0

Author

Odimar Fabeny, Apr 30 2012

Keywords

• nonn
• easy

Comments

Number of vertices into building blocks of 3d objects with 7 vertices.

Examples

			a(0) = 7+14+7;
a(0) = 7+14+28+14+7;
a(0) = 7+14+28+56+28+14+7;
a(0) = 7+14+28+56+112+56+28+14+7.
		

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..1000
• Index entries for linear recurrences with constant coefficients, signature (3,-2).

Crossrefs

Cf. A000045, A028399, A038578, A089143, A173033, A182461, A182462, A182464, A182466, A182467.

Programs

Mathematica

CoefficientList[Series[-((14 (x - 2))/(2 x^2 - 3 x + 1)), {x, 0, 40}], x] (* Vincenzo Librandi, Jun 01 2014 *)
LinearRecurrence[{3,-2},{28,70},30] (* Harvey P. Dale, Oct 05 2015 *)

Formula

a(n) = a(n-1)*2 + 14.

a(n) = 14*A153893(n). - Michel Marcus, Jun 01 2014

G.f.: -((14*(x-2))/(2*x^2-3*x+1)). - Vincenzo Librandi, Jun 01 2014