OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (3,-3,1).
FORMULA
G.f.: 27*x*(1 + x)/(1 - x)^3.
a(n) = 3*a(n-1) -3*a(n-2) +a(n-3) for n>2.
MATHEMATICA
Table[27 n^2, {n, 0, 40}]
PROG
(Magma) [27*n^2: n in [0..40]];
(PARI) a(n)=27*n^2 \\ Charles R Greathouse IV, Jun 17 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Jul 03 2014
EXTENSIONS
G.f. corrected by Bruno Berselli, Jul 03 2014
STATUS
approved