A020359 - OEIS

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A020359

Numbers k such that the continued fraction for sqrt(k) has period 20.

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 10 11:10 EST 2023. Contains 367710 sequences. (Running on oeis4.)