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A041575
Denominators of continued fraction convergents to sqrt(305).
2
1, 2, 13, 28, 965, 1958, 12713, 27384, 943769, 1914922, 12433301, 26781524, 923005117, 1872791758, 12159755665, 26192303088, 902698060657, 1831588424402, 11892228607069, 25616045638540, 882837780317429, 1791291606273398, 11630587417957817, 25052466442189032
OFFSET
0,2
FORMULA
G.f.: -(x^2-2*x-1)*(x^4+14*x^2+1) / (x^8-978*x^4+1). - Colin Barker, Nov 19 2013
a(n) = 978*a(n-4) - a(n-8) for n>7. - Vincenzo Librandi, Dec 20 2013
MATHEMATICA
Denominator[Convergents[Sqrt[305], 30]] (* Vincenzo Librandi, Dec 20 2013 *)
LinearRecurrence[{0, 0, 0, 978, 0, 0, 0, -1}, {1, 2, 13, 28, 965, 1958, 12713, 27384}, 30] (* Harvey P. Dale, Nov 03 2015 *)
PROG
(Magma) I:=[1, 2, 13, 28, 965, 1958, 12713, 27384]; [n le 8 select I[n] else 978*Self(n-4)-Self(n-8): n in [1..40]]; // Vincenzo Librandi, Dec 20 2013
CROSSREFS
Sequence in context: A294559 A041017 A033837 * A042917 A366720 A174049
KEYWORD
nonn,frac,easy
AUTHOR
EXTENSIONS
More terms from Colin Barker, Nov 19 2013
STATUS
approved