Numbers which can be expressed as the product of numbers made of only nines.

Terms

a(0) =1a(1) =9a(2) =81a(3) =99a(4) =729a(5) =891a(6) =999a(7) =6561a(8) =8019a(9) =8991a(10) =9801a(11) =9999a(12) =59049a(13) =72171a(14) =80919a(15) =88209a(16) =89991a(17) =98901a(18) =99999a(19) =531441a(20) =649539a(21) =728271a(22) =793881a(23) =809919a(24) =890109a(25) =899991a(26) =970299a(27) =989901a(28) =998001a(29) =999999