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A041177 Denominators of continued fraction convergents to sqrt(98). 2
1, 1, 9, 10, 189, 199, 1781, 1980, 37421, 39401, 352629, 392030, 7409169, 7801199, 69818761, 77619960, 1466978041, 1544598001, 13823762049, 15368360050, 290454242949, 305822602999, 2737035066941, 3042857669940, 57508473125861, 60551330795801, 541919119492269 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
LINKS
FORMULA
G.f.: (1 +x +9*x^2 +10*x^3 -9*x^4 +x^5 -x^6)/(1 -198*x^4 +x^8). - Vincenzo Librandi, Dec 12 2013
a(n) = 198*a(n-4) - a(n-8). - Vincenzo Librandi, Dec 12 2013
MATHEMATICA
Denominator[Convergents[Sqrt[98], 30]] (* or *) CoefficientList[Series[(1 + x + 9 x^2 + 10 x^3 - 9 x^4 + x^5 - x^6)/(1 - 198 x^4 + x^8), {x, 0, 30}], x] (* Vincenzo Librandi, Dec 12 2013 *)
PROG
(Magma) I:=[1, 1, 9, 10, 189, 199, 1781, 1980]; [n le 8 select I[n] else 198*Self(n-4)-Self(n-8): n in [1..40]]; // Vincenzo Librandi, Dec 12 2013
CROSSREFS
Cf. A041176.
Sequence in context: A360947 A248306 A336690 * A041178 A221201 A119159
KEYWORD
nonn,frac,easy
AUTHOR
EXTENSIONS
More terms from Vincenzo Librandi, Dec 12 2013
STATUS
approved

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Last modified May 25 04:23 EDT 2024. Contains 372782 sequences. (Running on oeis4.)