Shown with a cast-on count of 30 stitches.  

• Rows 1 and 5 (RS): K1, [k3, ctr dbl inc, k3] 4 times, k1 (38 sts).
• Rows 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, and 24: Purl.
• Rows 3 and 7: K1, [k2tog, k5, k2tog] 4 times, k1 (30 sts).
• Rows 9 and 11: K1, [k2tog, k1, ctr dbl inc, k1, k2tog] 4 times, k1.
• Rows 13 and 17: K1, [kfb, k5, kfb] 4 times, k1 (38 sts).
• Rows 15 and 19: K1, [k3, k3tog, k3] 4 times, k1 (30 sts).
• Rows 21 and 23: K1, [kfb, k1, k3tog, k1, kfb] 4 times, k1.