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A020359 Numbers k such that the continued fraction for sqrt(k) has period 20. 0
151, 199, 268, 367, 393, 412, 477, 511, 524, 537, 559, 606, 622, 790, 801, 863, 972, 996, 1002, 1044, 1065, 1079, 1151, 1182, 1195, 1216, 1353, 1356, 1374, 1388, 1397, 1408, 1415, 1454, 1500, 1502, 1510, 1513, 1528, 1537, 1603, 1612, 1687, 1791, 1854, 1859 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..46.

MATHEMATICA

cf20Q[n_]:=Module[{s=Sqrt[n]}, !IntegerQ[s]&&Length[ContinuedFraction[s][[2]]]==20]; Select[Range[2000], cf20Q] (* Harvey P. Dale, Mar 13 2013 *)

CROSSREFS

Sequence in context: A095745 A112796 A186459 * A185936 A050969 A247346

Adjacent sequences:  A020356 A020357 A020358 * A020360 A020361 A020362

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified December 3 05:05 EST 2021. Contains 349445 sequences. (Running on oeis4.)