OFFSET
0,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (0,0,0,798,0,0,0,-1).
FORMULA
G.f.: (19 + 20*x + 379*x^2 + 399*x^3 + 379*x^4 - 20*x^5 + 19*x^6 - x^7)/(1 - 798*x^4 + x^8). - Vincenzo Librandi, Nov 08 2013
a(n) = 798*a(n-4) - a(n-8). - Vincenzo Librandi, Nov 08 2013
MATHEMATICA
Numerator[Convergents[Sqrt[398], 30]] (* Harvey P. Dale, Nov 29 2012 *)
CoefficientList[Series[(19 + 20 x + 379 x^2 + 399 x^3 + 379 x^4 - 20 x^5 + 19 x^6 - x^7)/(1 - 798 x^4 + x^8), {x, 0, 30}], x] (* Vincenzo Librandi, Nov 08 2013 *)
PROG
(Magma) I:=[19, 20, 379, 399, 15541, 15940, 302461, 318401]; [n le 8 select I[n] else 798*Self(n-4)-Self(n-8): n in [1..30]]; // Vincenzo Librandi, Nov 08 2013
CROSSREFS
KEYWORD
nonn,cofr,frac,easy
AUTHOR
STATUS
approved