Improvised the foundation chain to simplify counting; original pattern has 5 chains per repeat, but I converted it to 3 ch + partial foundation sc (ch, draw yarn thru 2nd chain back, draw yarn thru both loops—one less step than a full fsc). This really helps get to a faster start because you don’t need to worry that you miscounted a 400+ stitch chain, nor do you need to count foundation chains when working Row 1 because the dc stitches go right into the foundation row’s sc stitches.

Each row after the foundation row has 502 st (5 st per repeat).