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A041837
Denominators of continued fraction convergents to sqrt(439).
2
1, 1, 20, 21, 860, 881, 17599, 18480, 756799, 775279, 15487100, 16262379, 665982260, 682244639, 13628630401, 14310875040, 586063632001, 600374507041, 11993179265780, 12593553772821, 515735330178620, 528328883951441, 10553984125255999, 11082313009207440
OFFSET
0,3
LINKS
FORMULA
G.f.: -(x^2-x-1)*(x^4+21*x^2+1) / (x^8-880*x^4+1). - Colin Barker, Nov 25 2013
a(n) = 880*a(n-4) - a(n-8) for n>7. - Vincenzo Librandi, Dec 25 2013
MATHEMATICA
Denominator[Convergents[Sqrt[439], 30]] (* Vincenzo Librandi, Dec 25 2013 *)
PROG
(Magma) I:=[1, 1, 20, 21, 860, 881, 17599, 18480]; [n le 8 select I[n] else 880*Self(n-4)-Self(n-8): n in [1..40]]; // Vincenzo Librandi, Dec 25 2013
CROSSREFS
Sequence in context: A063012 A302205 A041836 * A041838 A128356 A109212
KEYWORD
nonn,frac,easy,less
AUTHOR
EXTENSIONS
More terms from Colin Barker, Nov 25 2013
STATUS
approved