Harmonic numbers (A001599) with a record harmonic mean of divisors.

Terms

a(0) =1a(1) =6a(2) =28a(3) =140a(4) =270a(5) =672a(6) =1638a(7) =2970a(8) =8190a(9) =27846a(10) =30240a(11) =167400a(12) =237510a(13) =332640a(14) =695520a(15) =1421280a(16) =2178540a(17) =2457000a(18) =11981970a(19) =14303520a(20) =17428320a(21) =23963940a(22) =27027000a(23) =46683000a(24) =56511000a(25) =71253000a(26) =142990848a(27) =163390500a(28) =164989440a(29) =191711520