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.
%I A102750 #26 Oct 05 2020 12:26:32 %S A102750 2,3,5,6,7,10,11,12,13,14,15,17,19,20,21,22,23,24,26,28,29,30,31,33, %T A102750 34,35,37,38,39,40,41,42,43,44,45,46,47,48,51,52,53,55,56,57,58,59,60, %U A102750 61,62,63,65,66,67,68,69,70,71,73,74,76,77,78,79,80,82,83,84,85 %N A102750 Numbers n such that square of largest prime dividing n does not divide n. %C A102750 Numbers n such that the exponent of the largest prime dividing n is one. - _Harvey P. Dale_, May 02 2019 %C A102750 From _Peter Munn_, Sep 30 2020: (Start) %C A102750 2 together with numbers on the left half of the Doudna sequence tree depicted in _Antti Karttunen_'s 2014 comment in A005940. %C A102750 This sequence and A335738, considered as sets, are related by the self-inverse function A225546(.), which maps the members of either set 1:1 onto the other set. %C A102750 (End) %H A102750 Rémy Sigrist, <a href="/A102750/b102750.txt">Table of n, a(n) for n = 1..25000</a> %e A102750 63 is included because 63 = 3^2 *7 and 7 (the largest prime dividing 63) only divides 63 once. %t A102750 Select[Range[2,100],FactorInteger[#][[-1,2]]==1&] (* _Harvey P. Dale_, May 02 2019 *) %o A102750 (PARI) isok(n) = my(f = factor(n)); n % f[#f~, 1]^2; \\ _Michel Marcus_, May 20 2014 %Y A102750 Cf. A070003 (complement, apart from the term 1 that is in neither sequence). %Y A102750 Related to A335738 via A225546. %Y A102750 Cf. A005940. %K A102750 nonn %O A102750 1,1 %A A102750 _Leroy Quet_, Feb 09 2005 %E A102750 More terms from _Erich Friedman_, Aug 08 2005