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 A041065 Denominators of continued fraction convergents to sqrt(39). 2
 1, 4, 49, 200, 2449, 9996, 122401, 499600, 6117601, 24970004, 305757649, 1248000600, 15281764849, 62375059996, 763782484801, 3117504999200, 38173842475201, 155812874900004, 1907928341275249, 7787526240001000, 95358243221287249, 389220499125149996 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..200 Index entries for linear recurrences with constant coefficients, signature (0,50,0,-1). FORMULA G.f.: -(x^2-4*x-1) / (x^4-50*x^2+1). - Colin Barker, Nov 12 2013 a(n) = 50*a(n-2) - a(n-4). - Vincenzo Librandi, Dec 10 2013 MATHEMATICA Table[Denominator[FromContinuedFraction[ContinuedFraction[Sqrt[39], n]]], {n, 1, 50}] (* Vladimir Joseph Stephan Orlovsky, Mar 21 2011 *) Denominator[Convergents[Sqrt[39], 30]] (* Vincenzo Librandi, Dec 10 2013 *) PROG (Magma) I:=[1, 4, 49, 200]; [n le 4 select I[n] else 50*Self(n-2)-Self(n-4): n in [1..30]]; // Vincenzo Librandi, Dec 10 2013 CROSSREFS Cf. A010493, A041064. Sequence in context: A360883 A092866 A340662 * A166838 A166826 A295535 Adjacent sequences: A041062 A041063 A041064 * A041066 A041067 A041068 KEYWORD nonn,cofr,frac,easy AUTHOR N. J. A. Sloane. EXTENSIONS More terms from Colin Barker, Nov 12 2013 STATUS approved

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Last modified June 16 16:46 EDT 2024. Contains 373432 sequences. (Running on oeis4.)