OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (0,678,0,-1).
FORMULA
G.f.: -(x^2-13*x-1) / ((x^2-26*x-1)*(x^2+26*x-1)). - Colin Barker, Dec 07 2013
a(n) = 678*a(n-2) - a(n-4) for n>3. - Vincenzo Librandi, Jan 19 2014
MATHEMATICA
Denominator[Convergents[Sqrt[680], 30]] (* Vincenzo Librandi, Jan 19 2014 *)
PROG
(Magma) I:=[1, 13, 677, 8814]; [n le 4 select I[n] else 678*Self(n-2)-Self(n-4): n in [1..30]]; // Vincenzo Librandi, Jan 19 2014
CROSSREFS
KEYWORD
nonn,frac,easy
AUTHOR
EXTENSIONS
More terms from Colin Barker, Dec 07 2013
STATUS
approved