Regarding personnel No

Hi Gurus

I am a SAP-HR fresher.

i have created positions in Organisation Management.by putting that position id in Pa40.The personnel no what i am getting those personnel nos are not coming in sequantial.

Is there any rule so that i can get the personnel no in a sequancy.

also i have created so many paersonnel no. is it possible to make it in a sequancial order.

Thanks

Tejas