Thx for the answers!
Brian:
It worked just fine :)
If you have the following scenario:
row 23, 7001
row 24, 7002
row 25, 7003
row 26, 8001
row 27, 8002
row 28, 8003
If you stand on row 7001 and presses Ctrl + a you get 8004 on row 29, is it possible to get the next number in line...