A182464 a(n) = 3a(n-1) - 2a(n-2) with a(0)=24 and a(1)=60.

24, 60, 132, 276, 564, 1140, 2292, 4596, 9204, 18420, 36852, 73716, 147444, 294900, 589812, 1179636, 2359284, 4718580, 9437172, 18874356, 37748724, 75497460, 150994932, 301989876, 603979764, 1207959540, 2415919092, 4831838196, 9663676404, 19327352820, 38654705652

Offset: 0

Author

Odimar Fabeny, Apr 30 2012

Keywords

• easy
• nonn

Comments

Number of vertices into building blocks of 3d objects with 6 vertices.

Examples

			a(0) = 6+12+6;
a(1) = 6+12+24+12+6;
a(2) = 6+12+24+48+24+12+6;
a(3) = 6+12+24+48+96+48+24+12+6.
		

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, A182465, A182466, A182467.

Programs

Mathematica

CoefficientList[Series[-((12 (x - 2))/(2 x^2 - 3 x + 1)), {x, 0, 40}], x] (* Vincenzo Librandi, Jun 01 2014 *)
LinearRecurrence[{3,-2},{24,60},40] (* Harvey P. Dale, May 27 2018 *)

Formula

a(n) = a(n-1)*2 + 12.

a(n) = 12*A153893(n). - Michel Marcus, Jun 01 2014

G.f.: -((12*(x-2))/(2*x^2-3*x+1)). - Vincenzo Librandi, Jun 01 2014