Unitary superperfect numbers: numbers n such that usigma(usigma(n)) = 2*n, where usigma(n) is the sum of unitary divisors of n (A034448).

A038843

Unitary superperfect numbers: numbers n such that usigma(usigma(n)) = 2*n, where usigma(n) is the sum of unitary divisors of n (A034448).

Terms

    a(0) =2a(1) =9a(2) =165a(3) =238a(4) =1640a(5) =4320a(6) =10250a(7) =10824a(8) =13500a(9) =23760a(10) =58500a(11) =66912a(12) =425880a(13) =520128a(14) =873180a(15) =931392a(16) =1899744a(17) =2129400a(18) =2253888a(19) =3276000a(20) =4580064a(21) =4668300a(22) =13722800a(23) =15459840a(24) =40360320a(25) =201801600a(26) =439021440a(27) =3809332800a(28) =15359485680a(29) =794436968640

External references