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A031780 Period of continued fraction for sqrt(n) contains exactly 12 ones. 0
211, 214, 382, 385, 393, 436, 457, 487, 501, 511, 524, 526, 553, 559, 581, 614, 657, 716, 749, 781, 831, 846, 856, 862, 869, 875, 881, 893, 950, 996, 1002, 1019, 1046, 1094, 1123, 1132, 1137, 1169, 1194, 1234, 1246, 1266, 1309, 1334, 1353, 1359, 1361, 1372 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..48.

MATHEMATICA

cf12Q[n_]:=Module[{s=Sqrt[n]}, If[IntegerQ[s], 1, Count[ ContinuedFraction[ s][[2]], 1]] == 12]; Select[Range[1500], cf12Q] (* Harvey P. Dale, Jul 21 2015 *)

CROSSREFS

Sequence in context: A037272 A013530 A020365 * A036232 A064826 A333012

Adjacent sequences:  A031777 A031778 A031779 * A031781 A031782 A031783

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified September 24 01:27 EDT 2021. Contains 347617 sequences. (Running on oeis4.)