150281domain: NAppears in sequencesNonprime numbers k such that (k+1)*Sum_{d|k} 1/(d+1) is an integer.at n=22A069155a(n) = 4*n^3 - 6*n^2 + 1.at n=34A141530Intersection of A327653 and A327654.at n=28A327655Numbers whose arithmetic derivative (A003415) is a primorial number (A002110) > 1.at n=31A327978