OFFSET
0,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..1000
Wikipedia, Gegenbauer Polynomials
Index entries for linear recurrences with constant coefficients, signature (4,-22,36,-81).
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
KEYWORD
sign
AUTHOR
STATUS
approved