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 A233421 Let m = n-th nonsquare = A000037(n); then a(n) = A006255(m). 2

%I

%S 6,8,10,12,14,15,18,22,20,26,21,24,34,27,38,30,28,33,46,32,39,35,40,

%T 58,42,62,45,44,51,48,74,57,52,50,82,56,86,55,60,69,94,54,63,68,65,

%U 106,70,66,72,76,87,118,75,122,93,77,78,80,134,85,92,84

%N Let m = n-th nonsquare = A000037(n); then a(n) = A006255(m).

%H Peter Kagey, <a href="/A233421/b233421.txt">Table of n, a(n) for n = 1..5000</a>

%H AoPS Forum, <a href="http://www.artofproblemsolving.com/Forum/viewtopic.php?p=3315664">2013 Putnam Contest, Problem A2</a>, Dec 08 2013

%H R. L. Graham, <a href="http://www.jstor.org/stable/2689569">Bijection between integers and composites</a>, Problem 1242, Math. Mag., 60 (1987), p. 180. [Note that unless you subscribe to JSTOR this link will only show page 178, which contains a different problem proposed by R. L. Graham. - _N. J. A. Sloane_, Jan 13 2014]

%F a(n) = A006255(A000037(n)). - _Michel Marcus_, Jan 07 2014

%e a(1) = A006255(A000037(1)) = A006255(2) = 6 because 2*3*6 = 6^2.

%e a(2) = A006255(A000037(2)) = A006255(3) = 8 because 3*6*8 = 12^2.

%Y Arguments are numbers that are nonsquares: A000037.

%Y This is A006255 with perfect squares omitted.

%K nonn

%O 1,1

%A _Peter Kagey_, Dec 09 2013

%E Edited by _Michel Marcus_ and _N. J. A. Sloane_, Jan 13 2014

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Last modified July 19 08:49 EDT 2019. Contains 325155 sequences. (Running on oeis4.)