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A182464
a(n) = 3a(n-1) - 2a(n-2) with a(0)=24 and a(1)=60.
7
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
0,1
COMMENTS
Number of vertices into building blocks of 3d objects with 6 vertices.
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
EXAMPLE
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.
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 *)
KEYWORD
easy,nonn
AUTHOR
Odimar Fabeny, Apr 30 2012
STATUS
approved