OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (7,-17,17,-6).
FORMULA
G.f.: x*(6-27*x+31*x^2)/((1-2*x)*(1-3*x)*(1-x)^2). - Vincenzo Librandi, Feb 24 2013
a(n) = 7*a(n-1)-17*a(n-2)+17*a(n-3)-6*a(n-4). - Vincenzo Librandi, Feb 24 2013
MATHEMATICA
CoefficientList[Series[x (6 - 27 x + 31 x^2)/((1-2 x) (1-3 x) (1 - x)^2), {x, 0, 30}], x] (* Vincenzo Librandi, Feb 24 2013 *)
PROG
(Magma) [5*n+3^n-2^n: n in [0..30]] /* or */ I:=[0, 6, 15, 34]; [n le 4 select I[n] else 7*Self(n-1)-17*Self(n-2)+17*Self(n-3)-6*Self(n-4): n in [1..30]]; // Vincenzo Librandi, Feb 24 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Mohammad K. Azarian, Aug 18 2006
EXTENSIONS
Edited by Ray Chandler, Sep 06 2006
STATUS
approved