OFFSET
1,3
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
P. Barry, A. Hennessy, Meixner-Type Results for Riordan Arrays and Associated Integer Sequences, J. Int. Seq. 13 (2010) # 10.9.4, section 9.
Index entries for linear recurrences with constant coefficients, signature (-3,-3,-1).
FORMULA
From R. J. Mathar, Dec 07 2009: (Start)
a(n) = -3*a(n-1) - 3*a(n-2) - a(n-3).
G.f.: x*(1+3*x)/(1+x)^3. (End)
Sum_{n>2} 1/a(n) = -1/4. - Enrique Pérez Herrero, Dec 19 2015
MATHEMATICA
Table[(-1)^n*n*(n - 2), {n, 80}] (* Vladimir Joseph Stephan Orlovsky, Feb 14 2012 *)
CoefficientList[Series[(1+3*x)/(1+x)^3, {x, 0, 50}], x] (* Vincenzo Librandi, Jul 09 2012 *)
LinearRecurrence[{-3, -3, -1}, {1, 0, -3}, 50] (* Harvey P. Dale, Aug 25 2023 *)
PROG
(Magma) [(-1)^n*n*(n-2): n in [1..50]]; // Vincenzo Librandi, Jul 09 2012
(PARI) Vec(x*(1+3*x)/(1+x)^3 + O(x^100)) \\ Altug Alkan, Dec 19 2015
CROSSREFS
KEYWORD
sign,easy
AUTHOR
Jamel Ghanouchi, Aug 26 2008
EXTENSIONS
Entry completely rewriten by Jamel Ghanouchi, Nov 02 2009
Terms corrected by Jamel Ghanouchi, Nov 07 2009
Definition clarified; zeros skipped; sequence extended - R. J. Mathar, Dec 07 2009
STATUS
approved