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A025173
The Gegenbauer Polynomial of index n, order 1, evaluated at x=1/3 and multiplied by n*3^n/2.
1
0, 1, -5, -42, -22, 575, 1677, -3332, -27740, -23859, 259055, 832370, -981714, -10980437, -13342175, 85437240, 319499912, -192522535, -3642631389, -5753449394, 24313788850, 108290637399, -13811840779, -1096315586380, -2152355798868, 6240751807525
OFFSET
0,3
FORMULA
G.f.: ( x-9*x^2 ) / (1-2*x+9*x^2)^2 . - R. J. Mathar, Feb 05 2013
MAPLE
a:= n-> (<<0|1|0|0>, <0|0|1|0>, <0|0|0|1>, <-81|36|-22|4>>^n. <<0, 1, -5, -42>>)[1, 1]: seq(a(n), n=0..50); # Alois P. Heinz, Feb 05 2013
MATHEMATICA
Table[ n/2 3^n GegenbauerC[ n, 1, 1/3 ], {n, 24} ]
CROSSREFS
Sequence in context: A340535 A145008 A216610 * A222474 A327269 A266021
KEYWORD
sign
STATUS
approved