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A177371
Expansion of (1+12*x-24*x^2+8*x^4)/((1-8*x+4*x^2+4*x^3)*(1+2*x-2*x^2)).
0
1, 18, 98, 812, 5748, 43120, 316600, 2343120, 17290256, 127726400, 943159584, 6965532736, 51439836352, 379886330112, 2805462584192, 20718413985536, 153005867110656, 1129951564794880, 8344715027364352, 61625891492889600
OFFSET
0,2
REFERENCES
S. Kitaev, A. Burstein and T. 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.
FORMULA
From Harvey P. Dale, May 09 2011: (Start)
G.f.: (1+12*x-24*x^2+8*x^4)/((1-8*x+4*x^2+4*x^3)*(1+2*x-2*x^2)).
a(0)=1, a(1)=18, a(2)=98, a(3)=812, a(4)=5748, a(n)=6a(n-1)+ 14a(n-2) -28a(n-3) +8a(n-5). (End)
MATHEMATICA
CoefficientList[Series[(1+12x-24x^2+8x^4)/((1-8x+4x^2+4x^3)(1+2x-2x^2)), {x, 0, 20}], x] (* or *) LinearRecurrence[{6, 14, -28, 0, 8}, {1, 18, 98, 812, 5748}, 20] (* Harvey P. Dale, May 09 2011 *)
CROSSREFS
Sequence in context: A118864 A118606 A318063 * A044269 A044650 A008920
KEYWORD
nonn
AUTHOR
Signy Olafsdottir (signy06(AT)ru.is), May 07 2010
EXTENSIONS
Definition clarified by Harvey P. Dale, May 09 2011
STATUS
approved