MRP Period Start Dates logic for 4-4-5

I just look the BOM_PERIOD_START_DATES for 2018. It's not making a sense for me.

    PERIOD_NAME Week PERIOD_START_DATE NEXT_DATE PRIOR_DATE

1 JAN 01 1/1/2018 1/22/2018 11/20/2017

2 FEB 04 1/22/2018 2/19/2018 1/1/2018

3 MAR 08 2/19/2018 3/26/2018 1/22/2018

4 APR 13 3/26/2018 4/23/2018 2/19/2018

5 MAY 17 4/23/2018 5/21/2018 3/26/2018

6 JUN 21 5/21/2018 6/25/2018 4/23/2018

7 JUL 26 6/25/2018 7/23/2018 5/21/2018

8 AUG 30 7/23/2018 8/20/2018 6/25/2018

9 SEP 34 8/20/2018 9/24/2018 7/23/2018

10 OCT 39 9/24/2018 10/22/2018 8/20/2018

11 NOV 43 10/22/2018 11/19/2018 9/24/2018

12 DEC 47 11/19/2018 12/24/2018 10/22/2018

13 JAN 52 12/24/2018 1/21/2019 11/19/2018

Could you give me an example about 1st Qtr would look like?

Thanks,