A020364 - OEIS

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A020364

Numbers k such that the continued fraction for sqrt(k) has period 25.

457, 881, 1049, 1181, 1189, 1306, 1585, 1594, 1754, 2125, 2797, 2906, 4121, 4157, 4234, 4253, 4330, 4442, 4469, 4517, 4913, 5077, 5597, 6418, 7442, 8249, 8345, 8570, 8689, 8825, 9593, 10145, 10301, 10498, 10625, 10673, 10889, 11401, 11930, 12053 (list; graph; refs; listen; history; text; internal format)

	OFFSET	`1,1`
	LINKS	`Table of n, a(n) for n=1..40.`
	MATHEMATICA	`cf25Q[n_]:=Module[{s=Sqrt[n]}, If[IntegerQ[s], 1, Length[ ContinuedFraction[ s][[2]]]]==25]; Select[Range[13000], cf25Q] (* Harvey P. Dale, May 05 2020 *)`
	CROSSREFS	`Sequence in context: A325086 A215895 A142828 * A337847 A093058 A201257` `Adjacent sequences: A020361 A020362 A020363 * A020365 A020366 A020367`
	KEYWORD	`nonn`
	AUTHOR	`David W. Wilson`
	STATUS	`approved`

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Last modified December 4 01:48 EST 2023. Contains 367541 sequences. (Running on oeis4.)