OFFSET
1,1
LINKS
Daniel Starodubtsev, Table of n, a(n) for n = 1..10000
Index entries for linear recurrences with constant coefficients, signature (1,1,-1).
FORMULA
a(n) = 7*n - a(n-1) - 6 (with a(1)=2). - Vincenzo Librandi, Aug 05 2010
G.f.: x*(2 + 4*x + x^2) / ( (1+x)*(x-1)^2 ). - R. J. Mathar, Oct 25 2011
a(n) = 3*n + floor(n/2) - 1. - Arkadiusz Wesolowski, Sep 19 2012
E.g.f.: 1 + ((14*x - 5)*exp(x) + exp(-x))/4. - David Lovler, Sep 12 2022
MATHEMATICA
Table[3*n + Floor[n/2] - 1, {n, 100}] (* Paolo Xausa, Sep 02 2024 *)
PROG
(PARI) a(n) = 3*n + floor(n/2) - 1 \\ David Lovler, Sep 12 2022
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved