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URL: https://oeis.org/A020377

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A020377
Numbers k such that the continued fraction for sqrt(k) has period 38.
1
619, 669, 691, 811, 1057, 1108, 1357, 1461, 1629, 1723, 1809, 1816, 1819, 1857, 2084, 2169, 2182, 2185, 2201, 2246, 2266, 2356, 2391, 2515, 2571, 2578, 2634, 2950, 2959, 2979, 2983, 3139, 3235, 3254, 3382, 3411, 3441, 3460, 3473, 3558, 3574, 3621, 3714
OFFSET
1,1
LINKS
MATHEMATICA
q[k_] := Module[{c = ContinuedFraction[Sqrt[k]]}, Length[c] == 2 && Length[c[[2]]] == 38]; Select[Range[4000], q] (* Amiram Eldar, Aug 22 2025 *)
CROSSREFS
Cf. A003285.
Sequence in context: A288412 A234559 A251323 * A210887 A118467 A200812
KEYWORD
nonn
STATUS
approved