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A041615
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Denominators of continued fraction convergents to sqrt(326).
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2
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1, 18, 649, 11700, 421849, 7604982, 274201201, 4943226600, 178230358801, 3213089685018, 115849459019449, 2088503352035100, 75301970132283049, 1357523965733129982, 48946164736524962401, 882388489223182453200, 31814931776771093277601
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OFFSET
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0,2
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LINKS
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Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (0,650,0,-1).
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FORMULA
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G.f.: -(x^2-18*x-1) / (x^4-650*x^2+1). - Colin Barker, Nov 20 2013
a(n) = 650*a(n-2) - a(n-4) for n>3. - Vincenzo Librandi, Dec 22 2013
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MATHEMATICA
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Denominator[Convergents[Sqrt[326], 20]] (* Harvey P. Dale, Jul 06 2013 *)
CoefficientList[Series[(1 + 18 x - x^2)/(x^4 - 650 x^2 + 1), {x, 0, 30}], x] (* Vincenzo Librandi, Dec 22 2013 *)
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PROG
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(Magma) I:=[1, 18, 649, 11700]; [n le 4 select I[n] else 650*Self(n-2)-Self(n-4): n in [1..40]]; // Vincenzo Librandi, Dec 22 2013
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CROSSREFS
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Cf. A041614, A040307.
Sequence in context: A322889 A003298 A049869 * A041612 A046674 A073421
Adjacent sequences: A041612 A041613 A041614 * A041616 A041617 A041618
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KEYWORD
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nonn,frac,easy
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AUTHOR
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N. J. A. Sloane.
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EXTENSIONS
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More terms from Colin Barker, Nov 20 2013
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STATUS
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approved
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