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 A031635 Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 47. 0
 45877, 95033, 96269, 126961, 128389, 129106, 160289, 162698, 201065, 204665, 206477, 250441, 294293, 300833, 303029, 346369, 347546, 349906, 351089, 355841, 357034, 358229, 359426, 468697, 474185, 535322, 536785, 538250, 541186, 544130 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS MATHEMATICA opct47Q[n_]:=Module[{sqrt=Sqrt[n], cf, len}, cf=If[IntegerQ[sqrt], {}, ContinuedFraction[sqrt][[2]]]; len=Length[cf]; OddQ[len] && cf[[Floor[len/2]+1]] == 47] (* Harvey P. Dale, Sep 19 2012 *) CROSSREFS Sequence in context: A257358 A232255 A031841 * A159725 A210306 A223368 Adjacent sequences:  A031632 A031633 A031634 * A031636 A031637 A031638 KEYWORD nonn AUTHOR EXTENSIONS Corrected by Harvey P. Dale, Sep 19 2012 STATUS approved

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Last modified December 4 11:28 EST 2021. Contains 349486 sequences. (Running on oeis4.)