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This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A338792 a(n) is the least number k such that 1/prime(k) has repeating decimal expansion of period n.

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%I A338792 #10 Nov 09 2020 21:34:11
%S A338792 1,2,5,12,26,13,4,52,21,28693,1128,2431,1221,16,71954,11,7,153888,8,
%T A338792 27417323062119920,496,14,9,223378173194137397198,5760923,2403,149,
%U A338792 134,10,452,47,406,71,19,27,20,37607875619,150886,22544062111497849
%N A338792 a(n) is the least number k such that 1/prime(k) has repeating decimal expansion of period n.
%H A338792 <a href="/index/1#1overn">Index entries for sequences related to decimal expansion of 1/n</a>
%F A338792 a(0) = 1; a(n) = A000720(A007138(n)).
%e A338792 1/prime(1)  = 1/2  = 0.5 (finite decimal expansion).
%e A338792 1/prime(2)  = 1/3  = 0.3(3)... (period 1).
%e A338792 1/prime(5)  = 1/11 = 0.09(09)... (period 2).
%e A338792 1/prime(12) = 1/37 = 0.027(027)... (period 3).
%Y A338792 Cf. A000720, A002371, A003060, A007138.
%K A338792 nonn,base
%O A338792 0,2
%A A338792 _Ilya Gutkovskiy_, Nov 09 2020
%E A338792 a(19)-a(38) from _Daniel Suteu_, Nov 09 2020 [using data from A007138 and A234317]