66993domain: NAppears in sequencesa(n) = 7^n mod 2^n.at n=18A138616Natural growth of an aliquot sequence driven by a perfect number 2^(p-1)*((2^p) - 1).at n=24A146556Number of maximal subsets of {1..n} such that it is possible to choose a different binary index of each element.at n=27A370640