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 A233421 #39 Mar 25 2024 09:59:05 %S A233421 6,8,10,12,14,15,18,22,20,26,21,24,34,27,38,30,28,33,46,32,39,35,40, %T A233421 58,42,62,45,44,51,48,74,57,52,50,82,56,86,55,60,69,94,54,63,68,65, %U A233421 106,70,66,72,76,87,118,75,122,93,77,78,80,134,85,92,84 %N A233421 Let m = n-th nonsquare = A000037(n); then a(n) = A006255(m). %H A233421 Peter Kagey, <a href="/A233421/b233421.txt">Table of n, a(n) for n = 1..5000</a> %H A233421 William Lowell Putnam Competition, <a href="http://kskedlaya.org/putnam-archive/2013.pdf">Problem A2</a>, 2013. %H A233421 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 A233421 a(n) = A006255(A000037(n)). - _Michel Marcus_, Jan 07 2014 %e A233421 a(1) = A006255(A000037(1)) = A006255(2) = 6 because 2*3*6 = 6^2. %e A233421 a(2) = A006255(A000037(2)) = A006255(3) = 8 because 3*6*8 = 12^2. %Y A233421 Arguments are numbers that are nonsquares: A000037. %Y A233421 This is A006255 with perfect squares omitted. %K A233421 nonn %O A233421 1,1 %A A233421 _Peter Kagey_, Dec 09 2013 %E A233421 Edited by _Michel Marcus_ and _N. J. A. Sloane_, Jan 13 2014