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Smallest natural number k such that periodic part of 1/sqrt(k) is n (or 0 if no such number exists).
1

%I #21 Dec 11 2021 04:34:13

%S 1,81,2025,9,20736,324,36,1296,5184,1,9801,81,680625,2509056,

%T 160579584,4356,3828515625,37387847900390625,3025,164433494016,245025,

%U 680625,2025,95712890625,17015625,156816,627264,1936,40144896,59820556640625

%N Smallest natural number k such that periodic part of 1/sqrt(k) is n (or 0 if no such number exists).

%C I believe a(n) = 0 will eventually occur (see A037207).

%C The smallest n such that A037207(n) = 0 is n = 101, so the smallest n such that a(n) = 0 is n = 101 as well. - _Jianing Song_, Feb 06 2019

%F a(n) = A037207(n)^2. - _Henry Bottomley_

%e 1/sqrt(20736) = 0.0069444444444444444444...; a(4) = 20736.

%Y Cf. A037207.

%K nonn,base,nice

%O 0,2

%A _N. J. A. Sloane_

%E More terms from _Henry Bottomley_, Apr 28 2000