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) = 8*n - a(n-1) - 2, with n>1, a(1)=7.
G.f.: x*(7 + x^2)/((1+x)*(1-x)^2). - Vincenzo Librandi, Sep 18 2013
a(n) = a(n-1) +a(n-2) -a(n-3). - Vincenzo Librandi, Sep 18 2013
a(n) = 7 + 8*floor((n-1)/2). - Bruno Berselli, Sep 18 2013
E.g.f.: (-2 + exp(x) + (4*x + 1)*exp(2*x))*exp(-x). - G. C. Greubel, Jul 19 2016
MAPLE
MATHEMATICA
Table[4 n - 2 (-1)^n + 1, {n, 60}] (* Bruno Berselli, Sep 18 2013 *)
CoefficientList[Series[(7 + x^2)/((1 + x) (x - 1)^2), {x, 0, 70}], x] (* Vincenzo Librandi, Sep 18 2013 *)
PROG
(Magma) [4*n -2*(-1)^n + 1: n in [1..70]]; // Vincenzo Librandi, Sep 18 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Nov 24 2009
EXTENSIONS
Definition rewritten by Vincenzo Librandi, Sep 18 2013
STATUS
approved