120408domain: NAppears in sequencesNumbers k such that k*Sum_{d|k} 1/sigma(d) is an integer.at n=32A069166Partial sums of A129361.at n=21A227356Numbers of the form p^2 - 1 where p is a prime of the form 3*k-1 (A003627).at n=35A301812a(n) = 144*n^2 - 24*n (n>=1).at n=28A305072