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A002447 Expansion of 1/(1-2*x^2-3*x^3). 2
1, 0, 2, 3, 4, 12, 17, 36, 70, 123, 248, 456, 865, 1656, 3098, 5907, 11164, 21108, 40049, 75708, 143422, 271563, 513968, 973392, 1842625, 3488688, 6605426, 12505251, 23676916, 44826780, 84869585, 160684308 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (0,2,3).

FORMULA

a(n)=2a(n-2)+3a(n-3); a(n)=sum{k=0..floor(n/2), binomial(k, n-2k)2^k*(3/2)^(n-2k)}. - Paul Barry, Oct 16 2004

MATHEMATICA

CoefficientList[Series[1/(1-2*x^2-3*x^3), {x, 0, 40}], x] (* Vincenzo Librandi, Jun 11 2012 *)

PROG

(MAGMA) I:=[1, 0, 2]; [n le 3 select I[n] else 2*Self(n-2)+3*Self(n-3): n in [1..40]]; // Vincenzo Librandi, Jun 11 2012

(PARI) Vec(1/(1-2*x^2-3*x^3)+O(x^99)) \\ Charles R Greathouse IV, Sep 26 2012

CROSSREFS

Sequence in context: A210584 A060529 A048073 * A275067 A295620 A007499

Adjacent sequences:  A002444 A002445 A002446 * A002448 A002449 A002450

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified October 17 07:05 EDT 2018. Contains 316276 sequences. (Running on oeis4.)