Square root of the smallest square referenced in A237043 (Numbers n such that 2^n - 1 is not squarefree, but 2^d - 1 is squarefree for every proper divisor d of n.).

2

%I

%S 3,5,7,11,17,31,23,1093,43,73,29,127,89,47

%N Square root of the smallest square referenced in A237043 (Numbers n such that 2^n - 1 is not squarefree, but 2^d - 1 is squarefree for every proper divisor d of n.).

%e A273043(1)=6, 2^6-1=63, 63=3*3*7, 63 is not squarefree and the square is 3*3=9, the square root being 3.