Nonunitary doubly superperfect numbers: numbers k such that nusigma(nusigma(k)) = 2*k, where nusigma(k) = sigma(k) - usigma(k) is the sum of nonunitary divisors of k (A048146).
A329881
Nonunitary doubly superperfect numbers: numbers k such that nusigma(nusigma(k)) = 2*k, where nusigma(k) = sigma(k) - usigma(k) is the sum of nonunitary divisors of k (A048146).
Terms
- a(0) =4032a(1) =13104a(2) =58032a(3) =69648a(4) =237744a(5) =278592a(6) =365652a(7) =1114368a(8) =15333552a(9) =71319552a(10) =245364912a(11) =981465264a(12) =1141112832a(13) =4564451328a(14) =873139150710
External references
- oeis: A329881