min =: <.%:1020304050607080900 max =: <.%:1929394959697989990 range =: >.10%~max-min ns =: min+10*i.range squares =: *:ns strs =: ":"0 squares i =: I. '1234567890' -:"1 1 (2*i.10) {"1 1 strs problem206 =: i{ns