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 A050687 #23 Sep 04 2021 21:08:23 %S A050687 1,2,3,4,5,6,7,10,11,12,13,14,16,19,20,21,22,23,24,25,28,29,30,31,32, %T A050687 33,34,37,38,39,40,41,42,43,46,47,48,49,50,51,52,55,57,58,59,60,61,64, %U A050687 65,66,67,68,69,70,73,74,75,76,77,78,79,82,83,84,85,86,87 %N A050687 Numbers k such that A000422(k) is squarefree. %H A050687 Patrick De Geest, <a href="http://www.worldofnumbers.com/revfact.htm">Reversed Smarandache Concatenated Numbers, Prime factors from n down to 1</a> %H A050687 M. Fleuren, <a href="http://www.gallup.unm.edu/~smarandache/michafleuren.htm">Factors and primes of Smarandache sequences</a>. %H A050687 M. Fleuren, <a href="http://www.gallup.unm.edu/~smarandache/micha.txt">Smarandache Factors and Reverse factors</a> %H A050687 Carlos Rivera, <a href="http://www.primepuzzles.net/puzzles/puzz_008.htm">Puzzle 8. Primes by Listing</a>, The Prime Puzzles & Problems Connection. %Y A050687 Cf. A000422, A048288, A048342, A050675, A050688. %K A050687 nonn,base,hard %O A050687 1,2 %A A050687 _Patrick De Geest_, Aug 15 1999 %E A050687 More terms from and name clarified by _Sean A. Irvine_, Aug 17 2021 %E A050687 Offset changed to 1 by _Jinyuan Wang_, Sep 04 2021