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.: 144*x*(1+x)/(1-x)^3. - Bruno Berselli, Feb 10 2012
From Amiram Eldar, Jan 25 2021: (Start)
Sum_{n>=1} 1/a(n) = Pi^2/864.
Sum_{n>=1} (-1)^(n+1)/a(n) = Pi^2/1728.
Product_{n>=1} (1 + 1/a(n)) = sinh(Pi/12)/(Pi/12).
Product_{n>=1} (1 - 1/a(n)) = sin(Pi/12)/(Pi/12) = 3*sqrt(2)*(sqrt(3)-1)/Pi. (End)
MATHEMATICA
LinearRecurrence[{3, -3, 1}, {0, 144, 576}, 50] (* Vincenzo Librandi, Feb 10 2012 *)
(12 Range[0, 30])^2 (* Bruno Berselli, Feb 10 2012 *)
PROG
(Magma) [(12*n)^2: n in [0..35]]; // Vincenzo Librandi, Feb 10 2012
(PARI) a(n)=(12*n)^2 \\ Charles R Greathouse IV, Jun 17 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved