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A077866 Expansion of (1-x)^(-1)/(1 - x - 2*x^2 + 2*x^3). 6
1, 2, 5, 8, 15, 22, 37, 52, 83, 114, 177, 240, 367, 494, 749, 1004, 1515, 2026, 3049, 4072, 6119, 8166, 12261, 16356, 24547, 32738, 49121, 65504, 98271, 131038, 196573, 262108, 393179, 524250, 786393, 1048536, 1572823, 2097110, 3145685, 4194260, 6291411, 8388562 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Equals triangle A122196 * [1,2,4,8,16,...]. - Gary W. Adamson, Nov 29 2008

LINKS

Harvey P. Dale, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (2, 1, -4, 2).

FORMULA

a(n) = 2^(n/2)*(3 + 2*sqrt(2) + (3 - 2*sqrt(2))*(-1)^n) - n - 5. - Paul Barry, Apr 23 2004

a(n) = 2*a(n-1) + a(n-2) - 4*a(n-3) + 2*a(n-4); a(0)=1, a(1)=2, a(2)=5, a(3)=8. - Harvey P. Dale, Feb 16 2013

MATHEMATICA

CoefficientList[Series[(1-x)^(-1)/(1-x-2x^2+2x^3), {x, 0, 50}], x] (* or *) LinearRecurrence[{2, 1, -4, 2}, {1, 2, 5, 8}, 50] (* Harvey P. Dale, Feb 16 2013 *)

PROG

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

CROSSREFS

Bisections are A005803 and A050488.

Cf. A122196. - Gary W. Adamson, Nov 29 2008

Sequence in context: A024808 A238619 A323285 * A098894 A121641 A058884

Adjacent sequences:  A077863 A077864 A077865 * A077867 A077868 A077869

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Nov 17 2002

STATUS

approved

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Last modified November 12 09:29 EST 2019. Contains 329054 sequences. (Running on oeis4.)