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A041881
Denominators of continued fraction convergents to sqrt(462).
2
1, 2, 85, 172, 7309, 14790, 628489, 1271768, 54042745, 109357258, 4647047581, 9403452420, 399592049221, 808587550862, 34360269185425, 69529125921712, 2954583557897329, 5978696241716370, 254059825709984869, 514098347661686108, 21846190427500801405
OFFSET
0,2
FORMULA
G.f.: -(x^2 -2*x -1) / (x^4 -86*x^2 +1). - Colin Barker, Nov 26 2013
a(n) = 86*a(n-2) - a(n-4) for n>3. - Vincenzo Librandi, Dec 26 2013
MATHEMATICA
Denominator[Convergents[Sqrt[462], 30]] (* Harvey P. Dale, Sep 30 2011 *)
CoefficientList[Series[(1 + 2 x - x^2)/(x^4 - 86 x^2 + 1), {x, 0, 30}], x] (* Vincenzo Librandi, Dec 26 2013 *)
PROG
(Magma) I:=[1, 2, 85, 172]; [n le 4 select I[n] else 86*Self(n-2)-Self(n-4): n in [1..40]]; // Vincenzo Librandi, Dec 26 2013
CROSSREFS
Sequence in context: A244947 A078166 A101578 * A378031 A076542 A226842
KEYWORD
nonn,frac,easy
AUTHOR
EXTENSIONS
More terms from Colin Barker, Nov 26 2013
STATUS
approved