OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..10000
Index entries for linear recurrences with constant coefficients, signature (3,-3,1).
FORMULA
From Amiram Eldar, Jan 25 2021: (Start)
Sum_{n>=1} 1/a(n) = Pi^2/726.
Sum_{n>=1} (-1)^(n+1)/a(n) = Pi^2/1452.
Product_{n>=1} (1 + 1/a(n)) = sinh(Pi/11)/(Pi/11).
Product_{n>=1} (1 - 1/a(n)) = sin(Pi/11)/(Pi/11). (End)
G.f.: -((121*x*(1+x))/(-1+x)^3). - Harvey P. Dale, Nov 04 2021
MATHEMATICA
(11 Range[0, 30])^2 (* or *) LinearRecurrence[{3, -3, 1}, {0, 121, 484}, 30] (* Harvey P. Dale, Nov 04 2021 *)
PROG
(Magma) [(11*n)^2: n in [0..40]]; // Vincenzo Librandi, Sep 02 2011
(PARI) a(n)=(11*n)^2 \\ Charles R Greathouse IV, Jun 17 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved