Numbers sigma(k) when Sum_(j=1..k) sigma(j) / sigma(k) is an integer.

A168129

Numbers sigma(k) when Sum_(j=1..k) sigma(j) / sigma(k) is an integer.

Terms

    a(0) =1a(1) =4a(2) =30a(3) =444a(4) =1767a(5) =86250a(6) =97920a(7) =185700a(8) =584640a(9) =21954842a(10) =17654544432a(11) =357550809280a(12) =709346653572

External references