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A042457
Denominators of continued fraction convergents to sqrt(756).
2
1, 2, 109, 220, 11989, 24198, 1318681, 2661560, 145042921, 292747402, 15953402629, 32199552660, 1754729246269, 3541658045198, 193004263686961, 389550185419120, 21228714276319441, 42846978738058002, 2334965566131451549, 4712778111000961100
OFFSET
0,2
FORMULA
G.f.: -(x^2-2*x-1) / (x^4-110*x^2+1). - Colin Barker, Dec 14 2013
MATHEMATICA
Denominator[Convergents[Sqrt[756], 30]] (* Harvey P. Dale, Aug 17 2012 *)
CoefficientList[Series[(1 + 2 x - x^2)/(x^4 - 110 x^2 + 1), {x, 0, 30}], x] (* Vincenzo Librandi, Jan 22 2014 *)
PROG
(Magma) I:=[1, 2, 109, 220]; [n le 4 select I[n] else 110*Self(n-2)-Self(n-4): n in [1..30]]; // Vincenzo Librandi, Jan 22 2014
CROSSREFS
Sequence in context: A247098 A245056 A023281 * A062656 A173372 A323250
KEYWORD
nonn,frac,easy
AUTHOR
EXTENSIONS
Additional term from Colin Barker, Dec 14 2013
STATUS
approved