Shown with a cast-on count of 1 stitch.  

• Row 0 (WS): Ctr dbl inc (3 sts).
• Row 1: Ctr dbl inc, k1, ctr dbl inc (7 sts).
• Rows 2 and 4: K1, p5, k1.
• Rows 3 and 5: K1, kfb, sl2-k1-p2sso, kfb, k1.
• Row 6: K1, kfb, p3, kfb, k1 (9 sts).
• Rows 7 and 9: K1, kfb, k1, sl2-k1-p2sso, k1, kfb, k1.
• Row 8: K1, p7, k1.
• Row 10: K1, kfb, p5, kfb, k1 (11 sts).
• Rows 11, 13, and 15: K1, kfb, k2, sl2-k1-p2sso, k2, kfb, k1.
• Rows 12 and 14: K1, p9, k1.
• Row 16: K1, kfb, p7, kfb, k1 (13 sts).
• Row 17: K1, kfb, k3, sl2-k1-p2sso, k3, kfb, k1.
• Row 18: K1, kfb, p9, kfb, k1 (15 sts).
• Row 19: K1, kfb, k4, sl2-k1-p2sso, k4, kfb, k1.