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A031632
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 44.
0
485, 12569, 24074, 24698, 60637, 83113, 84269, 111781, 140914, 146213, 180137, 181837, 215737, 217597, 223225, 260629, 262673, 304226, 305329, 306434, 307541, 310874, 311989, 315346, 316469, 363133, 415577, 418157, 420745, 423341, 425945
OFFSET
1,1
MATHEMATICA
cf44Q[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]] == 44]; Select[Range[426000], cf44Q] (* Harvey P. Dale, May 10 2020 *)
CROSSREFS
Sequence in context: A158326 A031722 A156774 * A097767 A031520 A235525
KEYWORD
nonn
EXTENSIONS
First term 1937 removed by Georg Fischer, Jun 16 2019
First term (485) added and definition clarified by Harvey P. Dale, May 10 2020
STATUS
approved