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, 162, 0, -1).
FORMULA
a(n) = 162*a(n-2)-a(n-4). G.f.: -(x^2-4*x-1)/(x^4-162*x^2+1). [Colin Barker, Jul 16 2012]
MATHEMATICA
Denominator[Convergents[Sqrt[410], 30]] (* Harvey P. Dale, Nov 06 2011 *)
CoefficientList[Series[(1 + 4 x - x^2)/(x^4 - 162 x^2 + 1), {x, 0, 30}], x] (* Vincenzo Librandi, Dec 24 2013 *)
PROG
(Magma) I:=[1, 4, 161, 648]; [n le 4 select I[n] else 162*Self(n-2)-Self(n-4): n in [1..40]]; // Vincenzo Librandi, Dec 24 2013
CROSSREFS
KEYWORD
nonn,frac,easy
AUTHOR
EXTENSIONS
More terms from Vincenzo Librandi, Dec 24 2013
STATUS
approved