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%I #16 Jul 16 2021 02:42:53
%S 1297,5186,11667,20740,32405,46662,63511,82952,104985,129610,156827,
%T 186636,219037,254030,291615,331792,374561,419922,467875,518420,
%U 571557,627286,685607,746520,810025,876122,944811,1016092,1089965,1166430
%N Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 72.
%C a(n) = 1296n^2 + n for n < 75, but a(75) = 7102298. - _Charles R Greathouse IV_, Aug 04 2017
%H Charles R Greathouse IV, <a href="/A031750/b031750.txt">Table of n, a(n) for n = 1..10000</a>
%t cf72Q[n_]:=Module[{s=Sqrt[n]},If[IntegerQ[s],1,Min[ContinuedFraction[s][[2]]]]==72]; Select[Range[12*10^5],cf72Q] (* _Harvey P. Dale_, Jul 15 2020 *)
%K nonn
%O 1,1
%A _David W. Wilson_