OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (0,50,0,-1).
FORMULA
G.f.: (1 +2*x -x^2)/(x^4 -50*x^2 +1). - Vincenzo Librandi, Dec 14 2013
a(n) = 50*a(n-2) - a(n-4). - Vincenzo Librandi, Dec 14 2013
MATHEMATICA
Denominator[Convergents[Sqrt[156], 30]] (* or *) CoefficientList[Series[(1 + 2 x - x^2)/(x^4 - 50 x^2 + 1), {x, 0, 30}], x] (* Vincenzo Librandi, Dec 14 2013 *)
LinearRecurrence[{0, 50, 0, -1}, {1, 2, 49, 100}, 30] (* Harvey P. Dale, Aug 05 2015 *)
PROG
(Magma) I:=[1, 2, 49, 100]; [n le 4 select I[n] else 50*Self(n-2)-Self(n-4): n in [1..40]]; // Vincenzo Librandi, Dec 14 2013
CROSSREFS
KEYWORD
nonn,cofr,frac,easy
AUTHOR
EXTENSIONS
More terms from Vincenzo Librandi, Dec 14 2013
STATUS
approved