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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

Table of n, a(n) for n=0..29.

Index entries for linear recurrences with constant coefficients, signature (2,1,-2).

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 * A080275 A061349 A213780

Adjacent sequences:  A085275 A085276 A085277 * A085279 A085280 A085281

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 December 3 10:38 EST 2016. Contains 278699 sequences.