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, 0, 0, 0, 0, 0, 0, 2648, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1).
FORMULA
G.f.: -(x^4-3*x^3+4*x^2-2*x+1)*(x^4+2*x^3+4*x^2+3*x+1)*(x^10-21*x^5-1) / (x^20-2648*x^10+1). - Colin Barker, Nov 14 2013
a(n) = 2648*a(n-10) - a(n-20). - Vincenzo Librandi, Dec 15 2013
MATHEMATICA
Denominator[Convergents[Sqrt[159], 30]] (* Vincenzo Librandi, Dec 15 2013 *)
PROG
(Magma) I:=[1, 1, 2, 3, 5, 18, 23, 41, 64, 105, 2584, 2689, 5273, 7962, 13235, 47667, 60902, 108569, 169471, 278040]; [n le 20 select I[n] else 2648*Self(n-10)-Self(n-20): n in [1..40]]; // Vincenzo Librandi, Dec 15 2013
KEYWORD
nonn,frac,easy
AUTHOR
EXTENSIONS
More terms from Colin Barker, Nov 14 2013
STATUS
approved