OFFSET
0,3
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (0,0,0,126,0,0,0,-1).
FORMULA
G.f.: -(x^2-x-1)*(x^4+4*x^2+1) / (x^8-126*x^4+1). - Colin Barker, Nov 18 2013
a(n) = 126*a(n-4) - a(n-8) for n>7. - Vincenzo Librandi, Dec 18 2013
MATHEMATICA
Denominator[Convergents[Sqrt[248], 30]] (* Vincenzo Librandi, Dec 18 2013 *)
LinearRecurrence[{0, 0, 0, 126, 0, 0, 0, -1}, {1, 1, 3, 4, 123, 127, 377, 504}, 30] (* Harvey P. Dale, Apr 19 2019 *)
PROG
(Magma) I:=[1, 1, 3, 4, 123, 127, 377, 504]; [n le 8 select I[n] else 126*Self(n-4)-Self(n-8): n in [1..40]]; // Vincenzo Librandi, Dec 18 2013
CROSSREFS
KEYWORD
nonn,frac,easy
AUTHOR
EXTENSIONS
More terms from Colin Barker, Nov 18 2013
STATUS
approved