752571domain: NAppears in sequencesNumbers n such that n divides 2^n + 1.at n=37A006521Pseudo-powers to base 3: numbers k that are not powers of 3 such that k divides 2^k + 1.at n=24A016057Terms k of A006521 such that 2*k is a term of A124240.at n=34A289257