OFFSET
0,3
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,2158,0,0,0,0,0,-1).
FORMULA
G.f.: -(x^10 -x^9 +3*x^8 -13*x^7 +29*x^6 -42*x^5 -29*x^4 -13*x^3 -3*x^2 -x -1) / ((x^4 -13*x^2 +1)*(x^8 +13*x^6 +168*x^4 +13*x^2 +1)). - Colin Barker, Dec 06 2013
a(n) = 2158*a(n-6) - a(n-12) for n>11. - Vincenzo Librandi, Jan 19 2014
MAPLE
convert(sqrt(660), confrac, 30, cvgts): denom(cvgts); # Wesley Ivan Hurt, Dec 07 2013
MATHEMATICA
Denominator/@Convergents[Sqrt[660], 30] (* Harvey P. Dale, Jul 15 2011 *)
PROG
(Magma) I:=[1, 1, 3, 13, 29, 42, 2129, 2171, 6471, 28055, 62581, 90636]; [n le 12 select I[n] else 2158*Self(n-6)-Self(n-12): n in [1..40]]; // Vincenzo Librandi, Jan 19 2014
CROSSREFS
KEYWORD
nonn,frac,easy
AUTHOR
EXTENSIONS
More terms from Colin Barker, Dec 06 2013
STATUS
approved