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A116556
a(n) = 2*a(n-1) + 2*a(n-2), a(0)=0, a(1)=4.
1
0, 4, 8, 24, 64, 176, 480, 1312, 3584, 9792, 26752, 73088, 199680, 545536, 1490432, 4071936, 11124736, 30393344, 83036160, 226859008, 619790336, 1693298688, 4626178048, 12638953472, 34530263040
OFFSET
0,2
REFERENCES
F. Albert Cotton, Chemical Applications of Group Theory, Wiley-Interscience; 3 edition (March 2, 1990).
LINKS
Martin Burtscher, Igor Szczyrba, Rafał Szczyrba, Analytic Representations of the n-anacci Constants and Generalizations Thereof, Journal of Integer Sequences, Vol. 18 (2015), Article 15.4.5.
Tanya Khovanova, Recursive Sequences
FORMULA
From Philippe Deléham, Nov 19 2008: (Start)
a(n) = 4*A002605(n).
G.f.: 4x/(1-2x-2x^2). (End)
E.g.f.: (4/sqrt(3))*exp(x)*sinh(sqrt(3)*x). - G. C. Greubel, Oct 31 2016
MATHEMATICA
LinearRecurrence[{2, 2}, {0, 4}, 25] (* or *) Table[(2/sqrt(3))*( [1+sqrt(3)]^n - [1-sqrt(3)]^n ) , {n, 0, 25}] (* G. C. Greubel, Oct 31 2016 *)
CROSSREFS
Sequence in context: A099176 A190156 A291024 * A334324 A010366 A222356
KEYWORD
nonn,easy,less
AUTHOR
Roger L. Bagula, Mar 15 2006
EXTENSIONS
Edited by N. J. A. Sloane, Dec 04 2006
STATUS
approved