OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (0,244,0,-1).
FORMULA
G.f.: (1 + 11*x - x^2)/(1 - 244*x^2 + x^4). - Vincenzo Librandi, Dec 13 2013
a(n) = 244*a(n-2) - a(n-4). - Vincenzo Librandi, Dec 13 2013
MATHEMATICA
Denominator[Convergents[Sqrt[123], 30]] (* or *) CoefficientList[Series[(1 + 11 x - x^2)/(1 - 244 x^2 + x^4), {x, 0, 40}], x] (* Vincenzo Librandi, Dec 13 2013 *)
LinearRecurrence[{0, 244, 0, -1}, {1, 11, 243, 2684}, 20] (* Harvey P. Dale, Jul 27 2015 *)
PROG
(Magma) I:=[1, 11, 243, 2684]; [n le 4 select I[n] else 244*Self(n-2)-Self(n-4): n in [1..40]]; // Vincenzo Librandi, Dec 13 2013
CROSSREFS
KEYWORD
nonn,frac,easy
AUTHOR
EXTENSIONS
More terms from Vincenzo Librandi, Dec 13 2012
STATUS
approved