OFFSET
1,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (12,-54,108,-81).
FORMULA
G.f.: 18x^2(2+3x)/(1-3x)^4. - R. J. Mathar, Dec 19 2008
a(n) = 12*a(n-1) - 54*a(n-2) + 108*a(n-3) - 81*a(n-4). - Vincenzo Librandi, Feb 11 2013
MATHEMATICA
LinearRecurrence[{12, -54, 108, -81}, {0, 36, 486, 3888}, 30] (* Vincenzo Librandi, Feb 11 2013 *)
PROG
(Magma) [(n^3 - n^2)*3^n: n in [1..25]]; // Vincenzo Librandi, Feb 11 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Mohammad K. Azarian, Apr 30 2007
EXTENSIONS
Offset corrected by Mohammad K. Azarian, Nov 20 2008
STATUS
approved