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A031574 that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 76. 0
5778, 5794, 5806, 5822, 5826, 5854, 5862, 5874, 5878, 5926, 5938, 5942, 5958, 5998, 6018, 6022, 6038, 6046, 6062, 6082, 12999, 13017, 13044, 13071, 13089, 13143, 13173, 13182, 13188, 13251, 13254, 13269, 13287, 13323, 13326, 13341, 13353, 13377, 13389 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

MATHEMATICA

cf76Q[n_]:=Module[{s=Sqrt[n], cf, len}, cf=If[IntegerQ[s], {1}, ContinuedFraction[ s][[2]]]; len=Length[cf]; EvenQ[len]&&cf[[len/2]]== 76]; Select[ Range[14000], cf76Q] (* Harvey P. Dale, Aug 27 2019 *)

CROSSREFS

Sequence in context: A094411 A212423 A004933 * A004953 A004973 A114361

Adjacent sequences:  A031571 A031572 A031573 * A031575 A031576 A031577

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified December 1 22:12 EST 2021. Contains 349435 sequences. (Running on oeis4.)