Harmonic or Ore numbers: numbers k such that the harmonic mean of the divisors of k is an integer.

Terms

a(0) =1a(1) =6a(2) =28a(3) =140a(4) =270a(5) =496a(6) =672a(7) =1638a(8) =2970a(9) =6200a(10) =8128a(11) =8190a(12) =18600a(13) =18620a(14) =27846a(15) =30240a(16) =32760a(17) =55860a(18) =105664a(19) =117800a(20) =167400a(21) =173600a(22) =237510a(23) =242060a(24) =332640a(25) =360360a(26) =539400a(27) =695520a(28) =726180a(29) =753480