ps-line-number-step

ps-line-number-step is a variable defined in `ps-print.el'.
Its value is

1

Documentation:
Specify the interval that line number is printed.

For example, `ps-line-number-step' is set to 2, the printing will look like:

1 one line
one line
3 one line
one line
5 one line
one line
...

Valid values are:

integer an integer that specifies the interval that line number is
printed. If it's lesser than or equal to zero, it's used the
value 1.

`zebra' specifies that only the line number of the first line in a
zebra stripe is to be printed.

Any other value is treated as `zebra'.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 20 of Emacs.