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A139790
a(n) = (5*2^(n+2) - 3*n*2^n - 2*(-1)^n) / 18.
2
1, 2, 3, 5, 7, 9, 7, -7, -57, -199, -569, -1479, -3641, -8647, -20025, -45511, -101945, -225735, -495161, -1077703, -2330169, -5009863, -10718777, -22835655, -48467513, -102527431, -216239673, -454848967, -954437177, -1998352839, -4175662649, -8709239239
OFFSET
0,2
COMMENTS
Binomial transform of 1,1,0,1,-2,3,-8,13,-30,... (see A113954 and A103196). - R. J. Mathar, Feb 11 2010
FORMULA
a(n+1) - 2*a(n) = -A001045(n).
G.f.: (1 - x - 3*x^2)/((1+x)*(1-2*x)^2).
a(n) = 3*a(n-1) - 4*a(n-3).
MATHEMATICA
LinearRecurrence[{3, 0, -4}, {1, 2, 3}, 40] (* Harvey P. Dale, May 27 2018 *)
PROG
(Magma) [(5*2^(n+2)-3*n*2^n-2*(-1)^n) / 18: n in [0..35]]; // Vincenzo Librandi, Aug 09 2011
CROSSREFS
Sequence in context: A276227 A355269 A274698 * A118784 A193889 A177922
KEYWORD
sign,easy
AUTHOR
Paul Curtz, May 21 2008
EXTENSIONS
Definition replaced with closed formula by R. J. Mathar, Feb 11 2010
STATUS
approved