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A042920
Numerators of continued fraction convergents to sqrt(992).
2
31, 63, 3937, 7937, 496031, 999999, 62495969, 125991937, 7873996063, 15873984063, 992061007969, 1999996000001, 124991813008031, 251983622016063, 15747976378003937, 31747936378023937, 1984120031815488031, 3999988000008999999, 249983376032373487969
OFFSET
0,1
FORMULA
G.f.: (31 + 63*x + 31*x^2 - x^3)/(1 - 126*x^2 + x^4). - Vincenzo Librandi, Dec 09 2013
a(n) = 126*a(n-2) - a(n-4). - Vincenzo Librandi, Dec 09 2013
MATHEMATICA
Numerator[Convergents[Sqrt[992], 30]] (* or *) CoefficientList[Series[(31 + 63 x + 31 x^2 - x^3)/(1 - 126 x^2 + x^4), {x, 0, 30}], x] (* Vincenzo Librandi, Dec 09 2013 *)
PROG
(Magma) I:=[31, 63, 3937, 7937]; [n le 4 select I[n] else 126*Self(n-2)-Self(n-4): n in [1..30]]; // Vincenzo Librandi, Dec 09 2013
CROSSREFS
Cf. A042921.
Sequence in context: A042914 A042916 A042918 * A247438 A132772 A116324
KEYWORD
nonn,frac,easy
EXTENSIONS
More terms from Vincenzo Librandi, Dec 09 2013
STATUS
approved