%I #12 Mar 25 2015 00:25:58
%S 1,2,3,4,5,7,8,9,11,17,19,31,35
%N Numbers n such that n-th Catalan number is squarefree.
%C No more terms < 10000. - _Robert G. Wilson v_, Aug 28 2004
%H C. Rivera, <a href="http://www.primepuzzles.net/problems/prob_043.htm">Problem 43. Catalan Numbers</a> in www.primepuzzles.net
%t Select[Range[500], SquareFreeQ[CatalanNumber[ # ]] &]
%Y Cf. A000108.
%K nonn
%O 1,2
%A _Joseph L. Pe_, Mar 01 2003
%E Mathematica updated by _Jean-François Alcover_, Jul 04 2013