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 A166249 a(n) = 2*a(n-1) - a(n-3) + 2*a(n-4) for n>3, a(0)=a(1)=1, a(2)=0, a(3)=2. 1
 1, 1, 0, 2, 5, 12, 22, 43, 84, 170, 341, 684, 1366, 2731, 5460, 10922, 21845, 43692, 87382, 174763, 349524, 699050, 1398101, 2796204, 5592406, 11184811, 22369620, 44739242, 89478485, 178956972, 357913942, 715827883, 1431655764, 2863311530 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 LINKS G. C. Greubel, Table of n, a(n) for n = 0..1000 Index entries for linear recurrences with constant coefficients, signature (2,0,-1,2). FORMULA From R. J. Mathar, Nov 09 2009: (Start) G.f.: (1-x+3*x^3-2*x^2)/((1-2*x)*(1+x)*(x^2-x+1)). a(n) = A001045(n) + A010892(n+1). (End) MATHEMATICA LinearRecurrence[{2, 0, -1, 2}, {1, 1, 0, 2}, 100] (* G. C. Greubel, May 08 2016 *) CROSSREFS Sequence in context: A215183 A086734 A123647 * A326762 A116711 A247658 Adjacent sequences:  A166246 A166247 A166248 * A166250 A166251 A166252 KEYWORD nonn,easy AUTHOR Paul Curtz, Oct 10 2009 EXTENSIONS Edited by N. J. A. Sloane, Oct 13 2009 Extended by R. J. Mathar, Nov 09 2009 STATUS approved

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Last modified April 18 10:56 EDT 2021. Contains 343087 sequences. (Running on oeis4.)