A177140 Expansion of (1 + 4*x - x^2 - 2*x^3)/(1 - 3*x - 14*x^2 + 15*x^3 + 7*x^4).

1, 7, 34, 183, 913, 4742, 24025, 123487, 629290, 3223119, 16458937, 84196718, 430263457, 2200098535, 11245820674, 57495512631, 293914705105, 1502593292294, 7681432314169, 39269413869631, 200751991687114, 1026288131477583, 5246581043808697

Offset

1,2

Links

Table of n, a(n) for n=1..23.

Sergey Kitaev, Alexander Burstein and Toufik Mansour, Counting independent sets in certain classes of (almost) regular graphs, Pure Mathematics and Applications (PU.M.A.) 19 (2008), no. 2-3, 17-26.

Index entries for linear recurrences with constant coefficients, signature (3,14,-15,-7).

Formula

G.f.: (1 + 4*x - x^2 - 2*x^3)/(1 - 3*x - 14*x^2 + 15*x^3 + 7*x^4).

Mathematica

CoefficientList[Series[(1+4*x-x^2-2*x^3)/(1-3*x-14*x^2+15*x^3+7*x^4), {x, 0, 22}], x] (* Georg Fischer, Jun 11 2019 *)
LinearRecurrence[{3, 14, -15, -7}, {1, 7, 34, 183}, 30] (* Harvey P. Dale, Mar 10 2023 *)

Crossrefs

Sequence in context: A209807 A351588 A080048 * A027233 A117650 A365474

Adjacent sequences: A177137 A177138 A177139 * A177141 A177142 A177143

Keyword

nonn,easy

Author

Signy Olafsdottir (signy06(AT)ru.is), May 03 2010

Extensions

a(13) corrected by Georg Fischer, Jun 11 2019

Status

approved