cp's OEIS Frontend

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.

A164347 The n-th term is the minimum number x such that x/Totient(x) >= n.

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%I A164347 #20 Jul 19 2025 16:13:20
%S A164347 2,2,6,30,210,30030,223092870,13082761331670030,
%T A164347 3217644767340672907899084554130
%N A164347 The n-th term is the minimum number x such that x/Totient(x) >= n.
%C A164347 These numbers are all primorials. Primorials necessarily must be the minimum terms in this sequence (given the nature of Euler's Totient function).
%C A164347 Essentially the same as A091456. - _R. J. Mathar_, Aug 17 2009
%H A164347 Wikipedia, <a href="http://en.wikipedia.org/wiki/Euler&#39;s_totient_function">Euler's totient function</a>
%e A164347 2 => 2/totient(2) = 2 (so it is both the first and 2nd entry of the sequence).
%e A164347 30 => 30/totient(30) = 15/4 >= 3.
%e A164347 210 => 210/totient(210) = 210/48 >= 4.
%Y A164347 Each number n in this sequence is of the form: primorial(x). A164348, the related sequence, contains the x's.
%Y A164347 Cf. A073087, A091456.
%K A164347 easy,nonn
%O A164347 1,1
%A A164347 _Fred Schneider_, Aug 13 2009