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%I #11 Oct 30 2017 22:39:30
%S 1,2,3,5,5,7,9,11,13,13,13,17,19,19,19,23,25,29,29,31,32,32,32,37,37,
%T 37,41,41,43,43,47,49,53,53,53,53,59,61,61,64,64,67,67,67,71,73,73,73,
%U 73,79,81,83,83,83,83,89,89,89,89,89,97,101,101,103,103,103,107,109,109
%N a(n) = the largest prime power <= the n-th positive squarefree integer.
%C The first positive squarefree integer is considered to be 1 here.
%H Michael De Vlieger, <a href="/A156899/b156899.txt">Table of n, a(n) for n = 1..10000</a>
%t Block[{nn = 110, s}, s = Select[Range[nn], SquareFreeQ]; Map[If[# == 1, 1, SelectFirst[# - Range[0, # - 1], PrimePowerQ]] &, s]] (* _Michael De Vlieger_, Oct 30 2017 *)
%Y Cf. A081217, A156898, A156900, A005117, A000961.
%K nonn
%O 1,2
%A _Leroy Quet_, Feb 17 2009
%E Extended by _Ray Chandler_, Jun 19 2009
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