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 A031650 Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 62. 0

%I #16 Aug 18 2021 00:10:32

%S 48449,78481,80170,117085,118457,217381,218314,223009,279073,281189,

%T 284378,286514,348461,350825,357965,425545,511754,514618,516053,

%U 518929,521813,602801,605909,607466,612149,618421,619994,709693,719833,723229

%N Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 62.

%t cf62Q[n_]:=Module[{s=Sqrt[n],cf,len},cf=If[IntegerQ[s],{1,1},ContinuedFraction[ s][[2]]];len=Length[cf];OddQ[len]&&cf[[(len+1)/2]] == 62]; Select[Range[724000],cf62Q] (* _Harvey P. Dale_, Jun 21 2020 *)

%K nonn

%O 1,1

%A _David W. Wilson_

%E First term 3845 removed by _Georg Fischer_, Jun 16 2019

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Last modified December 5 03:48 EST 2023. Contains 367567 sequences. (Running on oeis4.)