Nonprimes in A066720.

Terms

a(0) =1a(1) =8a(2) =18a(3) =50a(4) =60a(5) =81a(6) =98a(7) =105a(8) =128a(9) =242a(10) =264a(11) =308a(12) =338a(13) =416a(14) =495a(15) =520a(16) =546a(17) =560a(18) =578a(19) =625a(20) =663a(21) =675a(22) =684a(23) =864a(24) =935a(25) =952a(26) =1029a(27) =1058a(28) =1083a(29) =1224