Write lines in Vim using a for loop

Question

How to make Vim write lines into a file according to a very simple arithmetic pattern?

Example:

foo1
foo2
foo3
...
foo99
foo100

I came up with the following solution using Ex commands

:for i in range(1,100)
:  execute "normal ofoo" . i
:endfor

but I am convinced there must be something more straightforward.

Answer 1

I would do it with macro.

First type one line:

foo1

then

qqYp<c-a>q

finally replay the macro:

98@q