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A078036
Expansion of (1-x)/(1+2*x^2+x^3).
1
1, -1, -2, 1, 5, 0, -11, -5, 22, 21, -39, -64, 57, 167, -50, -391, -67, 832, 525, -1597, -1882, 2669, 5361, -3456, -13391, 1551, 30238, 10289, -62027, -50816, 113765, 163659, -176714, -441083, 189769, 1058880, 61545, -2307529, -1181970, 4553513, 4671469, -7925056, -13896451, 11178643
OFFSET
0,3
FORMULA
G.f.: (1-x)/(1+2*x^2+x^3).
a(0)=1, a(1)=-1, a(2)=-2, a(n)=-2*a(n-2)-a(n-3). - Harvey P. Dale, Dec 18 2012
a(n)=A077967(n)-A077967(n-1). - R. J. Mathar, Mar 19 2025
MATHEMATICA
CoefficientList[Series[(1-x)/(1+2x^2+x^3), {x, 0, 50}], x] (* or *) LinearRecurrence[{0, -2, -1}, {1, -1, -2}, 50] (* Harvey P. Dale, Dec 18 2012 *)
PROG
(PARI) a(n)=([0, 1, 0; 0, 0, 1; -1, -2, 0]^n*[1; -1; -2])[1, 1] \\ Charles R Greathouse IV, Jun 02 2026
CROSSREFS
Cf. A077967.
Sequence in context: A338554 A317301 A131915 * A395538 A369865 A175178
KEYWORD
sign,easy
AUTHOR
N. J. A. Sloane, Nov 17 2002
STATUS
approved