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 A031625 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 37. 0
 8861, 27970, 41737, 42557, 43385, 58733, 77509, 99514, 127097, 183713, 185429, 214994, 215921, 217781, 218714, 219649, 220586, 223409, 224354, 250729, 252733, 262873, 290285, 292441, 303341, 333890, 335045, 336202, 337361, 338522, 339685 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Table of n, a(n) for n=1..31. MATHEMATICA cf37Q[n_]:=Module[{s=Sqrt[n], cf, len}, cf=If[IntegerQ[s], {1, 1}, ContinuedFraction[ s][[2]]]; len=Length[cf]; OddQ[len]&&cf[[(len+1)/2]] == 37]; Select[Range[350000], cf37Q] (* Harvey P. Dale, Jun 11 2019 *) CROSSREFS Sequence in context: A292572 A236031 A071564 * A046506 A116242 A116275 Adjacent sequences: A031622 A031623 A031624 * A031626 A031627 A031628 KEYWORD nonn AUTHOR David W. Wilson EXTENSIONS Corrected and extended, and definition clarified, by Harvey P. Dale, Jun 11 2019 STATUS approved

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Last modified May 29 00:29 EDT 2024. Contains 372921 sequences. (Running on oeis4.)