OFFSET
1,2
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
G.f.: x^2*(15 - 8*x) / ( (1+x)*(x-1)^2 ). - R. J. Mathar, Jan 05 2011
a(n) = a(n-1) +a(n-2) -a(n-3). - Vincenzo Librandi, - Feb 28 2012
E.g.f.: (1/4)*(23 - 32*exp(x) + (9 +14*x)*exp(2*x))*exp(-x). - G. C. Greubel, Jul 15 2016
MATHEMATICA
LinearRecurrence[{1, 1, -1}, {0, 15, 7}, 50] (* Vincenzo Librandi, Feb 28 2012 *)
PROG
(Magma) I:=[0, 15, 7]; [n le 3 select I[n] else Self(n-1)+Self(n-2)-Self(n-3): n in [1..40]]; // Vincenzo Librandi, Feb 28 2012
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Nov 20 2009
STATUS
approved