Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #23 Sep 04 2021 21:08:23
%S 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 33,34,37,38,39,40,41,42,43,46,47,48,49,50,51,52,55,57,58,59,60,61,64,
%U 65,66,67,68,69,70,73,74,75,76,77,78,79,82,83,84,85,86,87
%N Numbers k such that A000422(k) is squarefree.
%H Patrick De Geest, <a href="http://www.worldofnumbers.com/revfact.htm">Reversed Smarandache Concatenated Numbers, Prime factors from n down to 1</a>
%H M. Fleuren, <a href="http://www.gallup.unm.edu/~smarandache/michafleuren.htm">Factors and primes of Smarandache sequences</a>.
%H M. Fleuren, <a href="http://www.gallup.unm.edu/~smarandache/micha.txt">Smarandache Factors and Reverse factors</a>
%H Carlos Rivera, <a href="http://www.primepuzzles.net/puzzles/puzz_008.htm">Puzzle 8. Primes by Listing</a>, The Prime Puzzles & Problems Connection.
%Y Cf. A000422, A048288, A048342, A050675, A050688.
%K nonn,base,hard
%O 1,2
%A _Patrick De Geest_, Aug 15 1999
%E More terms from and name clarified by _Sean A. Irvine_, Aug 17 2021
%E Offset changed to 1 by _Jinyuan Wang_, Sep 04 2021