OFFSET
0,3
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (18,-108,216).
FORMULA
G.f.: 72*x^2/(1 - 6*x)^3. - Vincenzo Librandi, Feb 11 2013
a(n) = 72*A081136(n). - R. J. Mathar, Apr 26 2015
a(n) = 18*a(n-1) - 108*a(n-2) + 216*a(n-3). - Wesley Ivan Hurt, Jan 20 2024
MATHEMATICA
CoefficientList[Series[72 x^2/(1 - 6 x)^3, {x, 0, 30}], x] (* Vincenzo Librandi, Feb 11 2013 *)
LinearRecurrence[{18, -108, 216}, {0, 0, 72}, 30] (* Harvey P. Dale, Mar 22 2018 *)
PROG
(Magma) [(n^2-n)*6^n: n in [0..25]]; // Vincenzo Librandi, Feb 11 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Mohammad K. Azarian, Apr 07 2007
STATUS
approved