OFFSET
0,1
LINKS
FORMULA
G.f.: 9*(1 + 22*x + 9*x^2)/(1-x)^3.
a(n) = 9*A016814(n).
a(n) = a(n-1) + 288*n - 72, n >= 1. - Vincenzo Librandi, Mar 20 2011
MATHEMATICA
(12*Range[0, 30]+3)^2 (* or *) LinearRecurrence[{3, -3, 1}, {9, 225, 729}, 30] (* Harvey P. Dale, Aug 04 2015 *)
PROG
(PARI) a(n)=(12*n+3)^2 \\ Charles R Greathouse IV, Jun 17 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved