Remove rows that are not multiple of 7

[botolo99]

In OpenOffice Calc I have a list of 9000 rows with many values.

I want to remove all the rows that are not multiple of 7.

Example:

Row 1
Row 2
Row 3
Row 4
Row 5
Row 6
Row 7
Row 8
Row 9
Row 10
Row 11
Row 12
Row 13
Row 14
Row 15

Becomes:

Row 7
Row 14


How would you do that?

[Villeroy]

Add a calculated column =MOD(ROW();7)
Filter by >0
Delete rows
Remove filter