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A041635
Denominators of continued fraction convergents to sqrt(336).
2
1, 3, 109, 330, 11989, 36297, 1318681, 3992340, 145042921, 439121103, 15953402629, 48299328990, 1754729246269, 5312487067797, 193004263686961, 584325278128680, 21228714276319441, 64270468107087003, 2334965566131451549, 7069167166501441650
OFFSET
0,2
FORMULA
G.f.: -(x^2-3*x-1) / (x^4-110*x^2+1). - Colin Barker, Nov 20 2013
a(n) = 110*a(n-2) - a(n-4) for n>3. - Vincenzo Librandi, Dec 22 2013
MATHEMATICA
Denominator[Convergents[Sqrt[336], 30]] (* Vincenzo Librandi, Dec 22 2013 *)
PROG
(Magma) I:=[1, 3, 109, 330]; [n le 4 select I[n] else 110*Self(n-2)-Self(n-4): n in [1..40]]; // Vincenzo Librandi, Dec 22 2013
CROSSREFS
Sequence in context: A172271 A368623 A053861 * A272572 A142533 A089904
KEYWORD
nonn,frac,easy
AUTHOR
EXTENSIONS
Additional term from Colin Barker, Nov 20 2013
STATUS
approved