OFFSET
0,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (0,0,0,1762,0,0,0,-1).
FORMULA
G.f.: (31 + 63*x + 409*x^2 + 881*x^3 +409*x^4 -63*x^5 +31*x^6 -x^7)/(1 -1762*x^4 +x^8). - Vincenzo Librandi, Dec 09 2013
a(n) = 1762*a(n-4) - a(n-8). - Vincenzo Librandi, Dec 09 2013
MATHEMATICA
Numerator[Convergents[Sqrt[990], 30]] (* or *) CoefficientList[Series[(31 + 63 x + 409 x^2 + 881 x^3 + 409 x^4 - 63 x^5 + 31 x^6 - x^7)/(1 - 1762 x^4 + x^8), {x, 0, 30}], x] (* Vincenzo Librandi, Dec 09 2013 *)
LinearRecurrence[{0, 0, 0, 1762, 0, 0, 0, -1}, {31, 63, 409, 881, 55031, 110943, 720689, 1552321}, 30] (* Harvey P. Dale, Jun 07 2020 *)
PROG
(Magma) I:=[31, 63, 409, 881, 55031, 110943, 720689, 1552321]; [n le 8 select I[n] else 1762*Self(n-4)-Self(n-8): n in [1..30]]; // Vincenzo Librandi, Dec 09 2013
CROSSREFS
KEYWORD
nonn,cofr,frac,easy
AUTHOR
EXTENSIONS
More terms from Vincenzo Librandi, Dec 09 2013
STATUS
approved