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A261056
Expansion of ( 2-x^2 ) / (x^2+2*x-1)^2 .
1
2, 8, 27, 84, 248, 708, 1973, 5400, 14574, 38896, 102863, 269964, 703972, 1825612, 4711785, 12110064, 31010266, 79148184, 201420163, 511233156, 1294489296, 3270662036, 8247316765, 20758752648, 52163239622, 130875524096, 327893289783, 820410399804, 2050189683644
OFFSET
0,1
COMMENTS
2nd column of A210637.
FORMULA
a(n) = 2*A006645(n+2) -A006645(n).
MATHEMATICA
CoefficientList[Series[(2-x^2)/(x^2+2*x-1)^2, {x, 0, 40}], x] (* or *) LinearRecurrence[{4, -2, -4, -1}, {2, 8, 27, 84}, 40] (* Harvey P. Dale, Feb 24 2017 *)
CROSSREFS
Cf. A210637.
Sequence in context: A100505 A102759 A292698 * A295135 A076884 A138388
KEYWORD
nonn,easy
AUTHOR
R. J. Mathar, Aug 08 2015
STATUS
approved