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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.

A247180 Numbers with nonrepeating smallest prime factor.

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%I A247180 #26 Dec 08 2020 04:51:45
%S A247180 2,3,5,6,7,10,11,13,14,15,17,18,19,21,22,23,26,29,30,31,33,34,35,37,
%T A247180 38,39,41,42,43,46,47,50,51,53,54,55,57,58,59,61,62,65,66,67,69,70,71,
%U A247180 73,74,75,77,78,79,82,83,85,86,87,89,90,91,93,94,95,97,98
%N A247180 Numbers with nonrepeating smallest prime factor.
%C A247180 Complement of the union of {1} and A283050. The asymptotic density of this sequence is 1 - A283071 = 0.6699019646... - _Amiram Eldar_, Dec 08 2020
%H A247180 Reinhard Zumkeller, <a href="/A247180/b247180.txt">Table of n, a(n) for n = 1..10000</a>
%F A247180 a(n) mod A088377(a(n)) > 0;
%F A247180 A067029(a(n)) = 1.
%t A247180 Select[Range[100],FactorInteger[#][[1,2]]==1&] (* _Harvey P. Dale_, Jan 29 2020 *)
%o A247180 (Haskell)
%o A247180 a247180 n = a247180_list !! (n-1)
%o A247180 a247180_list = filter ((== 1) . a067029) [1..]
%o A247180 (PARI) isok(m) = (m>1) && (factor(m)[1,2] == 1); \\ _Michel Marcus_, Dec 08 2020
%Y A247180 Cf. A020639, A088377, A067029, A283050, A283071.
%Y A247180 Subsequences: A005117, A016825.
%K A247180 nonn
%O A247180 1,1
%A A247180 _Reinhard Zumkeller_, Nov 23 2014