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 A168418 a(n) = 9*n - a(n-1) - 8 with n>1, a(1)=5. 2
 5, 5, 14, 14, 23, 23, 32, 32, 41, 41, 50, 50, 59, 59, 68, 68, 77, 77, 86, 86, 95, 95, 104, 104, 113, 113, 122, 122, 131, 131, 140, 140, 149, 149, 158, 158, 167, 167, 176, 176, 185, 185, 194, 194, 203, 203, 212, 212, 221, 221, 230, 230, 239, 239, 248, 248, 257 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..1000 Index entries for linear recurrences with constant coefficients, signature (1,1,-1). FORMULA a(n) = (18*n - 9*(-1)^n - 7)/4. - Paolo P. Lava, Nov 27 2009 From R. J. Mathar, Jan 26 2010: (Start) a(n) = A168213(n-1), n>1. G.f.: x*(5 + 4*x^2)/((1+x)*(x-1)^2). (End) From G. C. Greubel, Jul 22 2016: (Start) a(n) = a(n-1) + a(n-2) - a(n-3). E.g.f.: (1/4)*(-9 + 16*exp(x) + (18*x - 7)*exp(2*x))*exp(-x). (End) MATHEMATICA LinearRecurrence[{1, 1, -1}, {5, 5, 14}, 60] (* Vincenzo Librandi, Feb 27 2012 *) PROG (MAGMA) I:=[5, 5, 14]; [n le 3 select I[n] else Self(n-1)+Self(n-2)-Self(n-3): n in [1..60]]; // Vincenzo Librandi, Feb 28 2012 CROSSREFS Sequence in context: A252768 A062367 A286257 * A266440 A294750 A247940 Adjacent sequences:  A168415 A168416 A168417 * A168419 A168420 A168421 KEYWORD nonn,easy AUTHOR Vincenzo Librandi, Nov 25 2009 STATUS approved

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