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A042249
Denominators of continued fraction convergents to sqrt(650).
2
1, 2, 101, 204, 10301, 20806, 1050601, 2122008, 107151001, 216424010, 10928351501, 22073127012, 1114584702101, 2251242531214, 113676711262801, 229604665056816, 11593909964103601, 23417424593264018, 1182465139627304501, 2388347703847873020
OFFSET
0,2
FORMULA
G.f.: -(x^2-2*x-1) / ((x^2-10*x-1)*(x^2+10*x-1)). - Colin Barker, Dec 05 2013
a(n) = 102*a(n-2) - a(n-4) for n>3. - Vincenzo Librandi, Jan 18 2014
MATHEMATICA
Denominator[Convergents[Sqrt[650], 30]] (* Harvey P. Dale, May 08 2012 *)
CoefficientList[Series[(1 + 2 x - x^2)/(x^4 - 102 x^2 + 1), {x, 0, 30}], x] (* Vincenzo Librandi, Jan 18 2014 *)
PROG
(Magma) I:=[1, 2, 101, 204]; [n le 4 select I[n] else 102*Self(n-2)-Self(n-4): n in [1..40]]; // Vincenzo Librandi, Jan 18 2014
CROSSREFS
Sequence in context: A100669 A142050 A195903 * A157338 A064152 A162353
KEYWORD
nonn,frac,easy
AUTHOR
EXTENSIONS
Additional term from Colin Barker, Dec 05 2013
STATUS
approved