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 A020418 Numbers k such that the continued fraction for sqrt(k) has period 79. 1
 1621, 3001, 3637, 4153, 5113, 5653, 7114, 8026, 9161, 12538, 12569, 13261, 14177, 18058, 19373, 21625, 25733, 25981, 26297, 28277, 28394, 29674, 30122, 32201, 32393, 32861, 33773, 34801, 35746, 36137, 36185, 36257, 36994, 39049, 39701, 41429, 43721 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Chai Wah Wu, Table of n, a(n) for n = 1..10000 MATHEMATICA cf79Q[n_]:=Module[{c=Sqrt[n]}, !IntegerQ[c]&&Length[ContinuedFraction[c][[2]]]==79]; Select[Range[50000], cf79Q] (* Harvey P. Dale, Dec 23 2012 *) PROG (Python) from sympy import continued_fraction_periodic A020418_list = [n for n, s in ((i, continued_fraction_periodic(0, 1, i)[-1]) for i in range(1, 10**5)) if isinstance(s, list) and len(s) == 79] # Chai Wah Wu, Jun 08 2017 CROSSREFS Sequence in context: A269212 A269095 A269274 * A347039 A224722 A045288 Adjacent sequences: A020415 A020416 A020417 * A020419 A020420 A020421 KEYWORD nonn AUTHOR David W. Wilson STATUS approved

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Last modified April 17 13:58 EDT 2024. Contains 371764 sequences. (Running on oeis4.)