Try something like this
dt = Current Data Table();
dt << Begin data update;
For( j = 1, j <= N Rows( dt ), j++,
For( i = 1, i <= 500, i++, //you might want to use length of the string than 500
dt << New Column( Word( i, Column( dt, 1 )[j], "" ) )
)
);
dt << End data update;