303769domain: NAppears in sequencesNumbers x such that sigma(x)=sigma(V(x)), where sigma(x) is the sum of the divisors of x and V(x) the transform defined in A245252.at n=32A245469Number of pairs of set partitions of {1,...,n} where every block of one is a subset or superset of some block of the other.at n=7A322442