A167291 a(n) = A137505(2n) + A137505(2n+1).
2, 2, 0, 0, 8, 8, -24, -24, 104, 104, -408, -408, 1640, 1640, -6552, -6552, 26216, 26216, -104856, -104856, 419432, 419432, -1677720, -1677720, 6710888, 6710888, -26843544, -26843544, 107374184, 107374184, -429496728, -429496728, 1717986920, 1717986920
Offset: 0
Links
- G. C. Greubel, Table of n, a(n) for n = 0..1000
- Index entries for linear recurrences with constant coefficients, signature (1,-4,4)
Programs
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Mathematica
CoefficientList[Series[(-2-6x^2)/((x-1)(4x^2+1)),{x,0,50}],x] (* or *) LinearRecurrence[{1,-4,4},{2,2,0},50] (* Harvey P. Dale, Jun 12 2013 *)
Formula
a(2n) = a(2n+1) = 2*(-1)^n*A109499(n).
G.f. ( -2-6*x^2 ) / ( (x-1)*(4*x^2+1) ). - R. J. Mathar, Feb 06 2011
a(0)=2, a(1)=2, a(2)=0, a(n) = a(n-1)-4*a(n-2)+4*a(n-3). - Harvey P. Dale, Jun 12 2013
Comments