Use a 3 ply yarn with a K hook
Pattern consists of DC in SC of previous row; SC in DC of previous row
Row 1: DC in 3rd chain from hook and across (18 dc); Ch 2 (or 3 depending on preference) and turn (turning chain counts as first DC now and throughout
Row 2: SC in second DC, DC, SC across; Ch 2 and turn
Row 3 - 9: Work in pattern; Ch 2 and turn
Row 10 - Continue to work in pattern, fastening off at end of row
Row 11: Chain 10 - Join to sleeve by working DC in first SC; work pattern across sleeve; Chain 11 and turn.
Row 12: SC in 3rd chain from hook, DC, SC, across - continue in pattern across sleeve and body (38 stitches)
Row 13 - 21: Continue to work in pattern; Ch 2 and turn.
Row 22 - 25: Work in pattern for first 20 stitches only; Ch 2 and turn
Row 26: Work in pattern across first 20 stitches; Ch 19 and turn
Row 27: SC in 3rd chain from hook; work DC, SC in pattern across to end; Ch 2 and turn
Row 28 - 35 Continue to work in pattern; Ch 2 and turn
Row 36: Work in pattern across row; fasten off
Row 37: Turn your work and insert hook in 11th stitch from edge; Ch 3 for first DC; work pattern for 18 stitches only (CH 3 will count as the first stitch) leave remaining 10 stitches unworked; Ch 2 and turn
Row 38 - 45: Continue to work in pattern; Ch 2 and turn
Row 46: DC in all stitches across; fasten off (cut 20" tail)
Sew side and underarm seams; weave in all loose ends
TRIM: Insert hook in bottom of sweater near either side seam; Ch 2 for first HDC; work HDCs evenly along bottom, 3 HDC in bottom/front edge corner; HDC along front edge, neckline, (2nd) front edge; 3 HDC in bottom/front edge corner; HDC around bottom edge; slip stitch to starting Ch 2 to join. Ch 2 for first HDC; work HDC in each HDC around with 3 HDC in center stitch on each corner; slip stitch to starting chain. I worked a total of three HDC trim rows - depending on the look you want, you could do more (for more of a shawl collar look) or less.
Sleeves can be folded for a cuff on smaller infants
Cut two lengths of narrow ribbon approximately 14" each; fold each in half and insert one folded edge through any space in the base HDC in front about 2/3 from bottom edge; loop folded edge over loose ends and tighten for a tie; repeat for other side (you may want to tack the loop with needle and thread to secure). If desired, you can weave a length of ribbon through the row of DC on edge of sleeves.