A168054 Expansion of (1-8x^2-24x^3)/((1-2x)^2*(1+2x+4x^2)).

1, 2, -4, -24, -48, -160, -448, -896, -2304, -5632, -11264, -26624, -61440, -122880, -278528, -622592, -1245184, -2752512, -6029312, -12058624, -26214400, -56623104, -113246208, -243269632, -520093696, -1040187392, -2214592512

Offset

0,2

Comments

Hankel transform of A168055.

Links

G. C. Greubel, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (2,0,8,-16).

Formula

a(n) = 2^n*A168053(n).

a(n) = 2*a(n-1) + 8*a(n-3) - 16*a(n-4) for n>3. - Vincenzo Librandi, Jul 08 2016

Mathematica

LinearRecurrence[{2, 0, 8, -16}, {1, 2, -4, -24}, 100] (* G. C. Greubel, Jul 07 2016 *)
CoefficientList[Series[(1 - 8 x^2 - 24 x^3) / ((1 - 2 x)^2 (1 + 2 x + 4 x^2)), {x, 0, 30}], x] (* Vincenzo Librandi, Jul 08 2016 *)

Prog

(Magma) I:=[1, 2, -4, -24]; [n le 4 select I[n] else 2*Self(n-1)+8*Self(n-3)-16*Self(n-4): n in [1..30]]; // Vincenzo Librandi, Jul 08 2016

Crossrefs

Cf. A168053, A168055.

Sequence in context: A350813 A262698 A347946 * A280075 A068506 A272640

Adjacent sequences: A168051 A168052 A168053 * A168055 A168056 A168057

Keyword

easy,sign

Author

Paul Barry, Nov 17 2009

Status

approved