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A085278 Expansion of (1+2x)^2/((1-x^2)(1-2x)). 2
1, 6, 17, 38, 81, 166, 337, 678, 1361, 2726, 5457, 10918, 21841, 43686, 87377, 174758, 349521, 699046, 1398097, 2796198, 5592401, 11184806, 22369617, 44739238, 89478481, 178956966, 357913937, 715827878, 1431655761, 2863311526 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
Binomial transform is A085277.
LINKS
FORMULA
a(n)=16*2^n/3+(-1)^n/6-9/2.
G.f.: (2*x+1)^2 / ( (x-1)*(2*x-1)*(1+x) ). - R. J. Mathar, Nov 20 2014
MATHEMATICA
CoefficientList[Series[(1+2x)^2/((1-x^2)(1-2x)), {x, 0, 40}], x] (* or *) LinearRecurrence[{2, 1, -2}, {1, 6, 17}, 40] (* Harvey P. Dale, Sep 19 2016 *)
CROSSREFS
Sequence in context: A000385 A192756 A004799 * A366104 A080275 A061349
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Jun 25 2003
EXTENSIONS
Missing parenthesis in definition corrected by Harvey P. Dale, Sep 19 2016
STATUS
approved

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Last modified May 23 18:34 EDT 2024. Contains 372765 sequences. (Running on oeis4.)