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A168150
Inverse binomial transform of A026741.
1
0, 1, -1, 3, -8, 20, -48, 112, -256, 576, -1280, 2816, -6144, 13312, -28672, 61440, -131072, 278528, -589824, 1245184, -2621440, 5505024, -11534336, 24117248, -50331648, 104857600, -218103808, 452984832, -939524096, 1946157056, -4026531840, 8321499136, -17179869184
OFFSET
0,4
FORMULA
a(n+2) = (-1)^(n+1) * A001792(n).
From R. J. Mathar, Nov 23 2009: (Start)
a(n) = -4*a(n-1) -4*a(n-2) = (-2)^(n-3)*n, n>3.
G.f.: x*(1 + 3*x + 3*x^2)/(1 + 2*x)^2. (End)
MATHEMATICA
Join[{0, 1, -1, 3}, LinearRecurrence[{-4, -4}, {-8, 20}, 50]] (* G. C. Greubel, Jul 14 2016 *)
CoefficientList[Series[x (1 + 3 x + 3 x^2) / (1 + 2 x)^2, {x, 0, 33}], x] (* Vincenzo Librandi, Jul 15 2016 *)
PROG
(PARI) a(n)=(-2)^if(n>1, n-3)*n \\ M. F. Hasler, Jan 25 2012
(Magma) [0, 1] cat [(-2)^(n-3)*n: n in [2..35]]; // Vincenzo Librandi, Jul 15 2016
CROSSREFS
KEYWORD
sign,easy
AUTHOR
Paul Curtz, Nov 19 2009
EXTENSIONS
Comments turned into formulas, out-of-scope material moved to A026741 by R. J. Mathar, Nov 23 2009
STATUS
approved