Dear SeqFans! Are there numbers n such that n divides 2^n+1 and (2^n+1)/n is not squarefree? Cf. https://oeis.org/A006521 and https://oeis.org/A272361 Best regards, Thomas ________ Are there numbers n such that n-1 divides 2^n-2 and (2^n-2)/(n-1) is not squarefree? Cf. https://oeis.org/draft/A069051 (see my Conjecture and Discussion). https://oeis.org/A272359