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A042747
Denominators of continued fraction convergents to sqrt(904).
2
1, 15, 901, 13530, 812701, 12204045, 733055401, 11008035060, 661215159001, 9929235420075, 596415340363501, 8956159340872590, 537965975792718901, 8078445796231656105, 485244713749692085201, 7286749152041612934120, 437690193836246468132401
OFFSET
0,2
FORMULA
a(0)=1, a(1)=15, a(2)=901, a(3)=13530, a(n)=902*a(n-2)-a(n-4). - Harvey P. Dale, Sep 25 2013
G.f.: -(x^2-15*x-1) / ((x^2-30*x-1)*(x^2+30*x-1)). - Colin Barker, Nov 19 2013
MATHEMATICA
Denominator[Convergents[Sqrt[904], 30]] (* or *) LinearRecurrence[ {0, 902, 0, -1}, {1, 15, 901, 13530}, 30] (* Harvey P. Dale, Sep 25 2013 *)
PROG
(Magma) I:=[1, 15, 901, 13530]; [n le 4 select I[n] else 902*Self(n-2)-Self(n-4): n in [1..30]]; // Vincenzo Librandi, Jan 28 2014
CROSSREFS
Sequence in context: A249963 A157462 A268166 * A324423 A261067 A136419
KEYWORD
nonn,frac,easy
AUTHOR
EXTENSIONS
Additional term from Colin Barker, Nov 19 2013
STATUS
approved