A105811 Expansion of g.f. (1+x-x^2)/(1+x)^2.
1, -1, 0, 1, -2, 3, -4, 5, -6, 7, -8, 9, -10, 11, -12, 13, -14, 15, -16, 17, -18, 19, -20, 21, -22, 23, -24, 25, -26, 27, -28, 29, -30, 31, -32, 33, -34, 35, -36, 37, -38, 39, -40, 41, -42, 43, -44, 45, -46, 47, -48, 49, -50, 51, -52, 53, -54, 55, -56, 57, -58, 59, -60, 61, -62, 63, -64, 65
Offset: 0
Links
- Index entries for linear recurrences with constant coefficients, signature (-2,-1).
Crossrefs
Cf. A105810.
Programs
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Mathematica
CoefficientList[Series[(1+x-x^2)/(1+x)^2,{x,0,70}],x] (* or *) LinearRecurrence[ {-2,-1},{1,-1,0},70] (* Harvey P. Dale, Jun 16 2016 *) -
PARI
a(n)=-0^n-(-1)^n*(n-2) \\ Charles R Greathouse IV, Sep 02 2015
Formula
a(n) = -0^n-(-1)^n*(n-2).
E.g.f.: exp(-x)*(2 + x) - 1. - Stefano Spezia, Dec 29 2024
Comments