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A031576 Numbers k such 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 78. 0
6086, 6098, 6102, 6114, 6134, 6158, 6166, 6182, 6194, 6198, 6226, 6238, 6246, 6278, 6294, 6302, 6306, 6326, 6334, 6338, 6358, 6374, 6382, 6398, 13692, 13701, 13737, 13749, 13758, 13764, 13773, 13791, 13809, 13863, 13881, 13917, 13929, 13953, 13989 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
MATHEMATICA
cf78Q[n_]:=Module[{s=Sqrt[n], cf, len}, cf=If[IntegerQ[s], {1}, ContinuedFraction[s][[2]]]; len = Length[ cf]; EvenQ[len]&&cf[[len/2]]==78]; Select[Range[14000], cf78Q] (* Harvey P. Dale, Jan 31 2024 *)
CROSSREFS
Sequence in context: A084804 A274360 A025515 * A204966 A252329 A156200
KEYWORD
nonn
AUTHOR
STATUS
approved

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Last modified April 20 16:19 EDT 2024. Contains 371844 sequences. (Running on oeis4.)