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A020380 Numbers k such that the continued fraction for sqrt(k) has period 41. 0
1117, 1657, 2965, 3209, 3385, 3418, 3449, 3917, 3985, 4306, 4537, 4721, 5594, 5717, 5897, 6817, 7978, 8458, 8917, 9125, 9437, 10685, 11441, 12074, 12634, 12805, 13498, 14866, 15101, 15413, 15482, 16106, 16525, 16565, 16570, 18149, 18233, 18394, 18925 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..39.

MATHEMATICA

cfp41Q[n_]:=Module[{s=Sqrt[n]}, If[IntegerQ[s], 1, Length[ ContinuedFraction[s][[2]]]]==41]; Select[Range[20000], cfp41Q] (* Harvey P. Dale, Jan 28 2017 *)

CROSSREFS

Cf. A003285.

Sequence in context: A258691 A221428 A161848 * A243527 A251360 A201034

Adjacent sequences:  A020377 A020378 A020379 * A020381 A020382 A020383

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified November 27 16:35 EST 2021. Contains 349394 sequences. (Running on oeis4.)