OFFSET
0,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (0,0,0,674,0,0,0,-1).
FORMULA
G.f.: (25 +26*x +311*x^2 +337*x^3 +311*x^4 -26*x^5 +25*x^6 -x^7)/(1 -674*x^4 +x^8). - Vincenzo Librandi, Nov 21 2013
a(n) = 674*a(n-4) - a(n-8). - Vincenzo Librandi, Nov 21 2013
MATHEMATICA
Numerator[Convergents[Sqrt[672], 30]] (* or *) CoefficientList[Series[(25 + 26 x + 311 x^2 + 337 x^3 + 311 x^4 - 26 x^5 + 25 x^6 - x^7)/(1 - 674 x^4 + x^8), {x, 0, 30}], x] (* Vincenzo Librandi, Nov 21 2013 *)
PROG
(Magma) I:=[25, 26, 311, 337, 17161, 17498, 209639, 227137]; [n le 8 select I[n] else 674*Self(n-4)-Self(n-8): n in [1..30]]; // Vincenzo Librandi, Nov 21 2013
CROSSREFS
KEYWORD
nonn,cofr,frac,easy
AUTHOR
STATUS
approved