OFFSET
1,2
COMMENTS
a(n) = A166598(n-1) for n > 1. - Georg Fischer, Oct 14 2018
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) = 5*n - a(n-1) - 5, with n > 1, a(1)=0.
G.f.: 5*x^2/((1+x)*(x-1)^2). - Vincenzo Librandi, Sep 16 2013
a(n) = 5*A004526(n). - Bruno Berselli, Sep 17 2013
E.g.f.: (5/4)*(1 + (2*x - 1)*exp(2*x))*exp(-x). - G. C. Greubel, Jul 17 2016
MATHEMATICA
CoefficientList[Series[5 x/((1 + x) (x - 1)^2), {x, 0, 70}], x] (* Vincenzo Librandi, Sep 16 2013 *)
Table[5 n/2 + 5 (-1)^n/4 - 5/4, {n, 70}] (* Bruno Berselli, Sep 17 2013 *)
PROG
(Magma) [n le 1 select (n-1) else 5*n-Self(n-1)-5: n in [1..70]]; // Vincenzo Librandi, Sep 16 2013
CROSSREFS
KEYWORD
nonn,easy,less
AUTHOR
Vincenzo Librandi, Nov 22 2009
EXTENSIONS
New definition by Bruno Berselli, Sep 17 2013
STATUS
approved