OFFSET
0,1
LINKS
T. D. Noe, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (3,-3,1).
FORMULA
a(n) = 242*n + a(n-1) with a(0)=10. - Vincenzo Librandi, Nov 12 2010
G.f.: -2*(5+111*x+5*x^2)/(x-1)^3 . - R. J. Mathar, May 30 2022
From Amiram Eldar, Feb 20 2023: (Start)
Sum_{n>=0} 1/a(n) = cot(Pi/11)*Pi/99.
Product_{n>=0} (1 - 1/a(n)) = cosec(Pi/11)*cos(sqrt(85)*Pi/22).
Product_{n>=0} (1 + 1/a(n)) = cosec(Pi/11)*cos(sqrt(77)*Pi/22). (End)
MATHEMATICA
Table[(11*n + 1)*(11*n + 10), {n, 0, 40}] (* Amiram Eldar, Feb 20 2023 *)
PROG
(PARI) a(n)=(11*n+1)*(11*n+10) \\ Charles R Greathouse IV, Jun 16 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved