Loop stitch with double crochet is a one of the basic crochet stitches.
double crochet loop stitch (ring double crochet)
At all crochet schemes loop stitch with double crochet symbol would appear as:
At the scheme below you can see a stitches of loop stitch with double crochet.
Loop stitch with double crochet instructions
Chain three stitches, yarn over, and wrap the yarn over the index finger of your yarn hand.
Insert hook in the last stitch of the previous row under top two loops. Grab the strand of yarn from behind your index finger, and draw the yarn through the stitch.
Work one double crochet.
Take the loop off your finger.
You should now see a row of loops on the wrong side of your fabric.
Save this step by step tutorial as a reminder