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 A168376 a(n) = (14*n - 7*(-1)^n - 9)/4. 2
 3, 3, 10, 10, 17, 17, 24, 24, 31, 31, 38, 38, 45, 45, 52, 52, 59, 59, 66, 66, 73, 73, 80, 80, 87, 87, 94, 94, 101, 101, 108, 108, 115, 115, 122, 122, 129, 129, 136, 136, 143, 143, 150, 150, 157, 157, 164, 164, 171, 171, 178, 178, 185, 185, 192, 192, 199, 199, 206 (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) = 7*n - a(n-1) - 8, with n>1, a(1)=3. a(n) = A168331(n-1), n>1. - R. J. Mathar, Nov 25 2009 G.f.: x*(3 + 4*x^2)/((1+x) * (x-1)^2). - R. J. Mathar, Nov 25 2009 a(n) = 3 + 7*floor((n-1)/2). - Bruno Berselli, Sep 18 2013 From G. C. Greubel, Jul 19 2016: (Start) E.g.f.: (1/4)*(-7 + 16*exp(x) + (14*x - 9)*exp(2*x))*exp(-x). a(n) = a(n-1) + a(n-2) - a(n-3). (End) MATHEMATICA Table[7 n/2 - (7 (-1)^n + 9)/4, {n, 60}] (* Bruno Berselli, Sep 17 2013 *) CoefficientList[Series[(3 + 4 x^2)/((1 + x) (x - 1)^2), {x, 0, 70}], x] (* Vincenzo Librandi, Sep 17 2013 *) PROG (MAGMA) [n eq 1 select 3 else 7*n-Self(n-1)-8: n in [1..70]]; // Vincenzo Librandi, Sep 17 2013 (PARI) a(n)=(14*n-7*(-1)^n-9)/4 \\ Charles R Greathouse IV, Jul 19 2016 CROSSREFS Cf. A168331. Sequence in context: A134704 A057210 A278832 * A266221 A073709 A085288 Adjacent sequences:  A168373 A168374 A168375 * A168377 A168378 A168379 KEYWORD nonn,easy AUTHOR Vincenzo Librandi, Nov 24 2009 EXTENSIONS Definition rewritten using Mathar's formula by Bruno Berselli, Sep 17 2013 STATUS approved

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Last modified July 21 22:02 EDT 2019. Contains 325210 sequences. (Running on oeis4.)