Here's the pattern:
Cast on 20 stitches.
Odd number rows: Knit 5, purl 2, knit 6, purl 2, knit 5.
Even number rows: Knit 7, purl 6, knit 7.
Every now and then on an odd row: Cross 3 over 3 on the center 6 stitches. (You know, like a cable.) Always cross them in the same direction.
Seam the ends together any way you like when you think the band is the correct circumference. I don't recommend using a provisional cast on and then trying to kitchener the ends together unless you know how to do that in garter stitch, and purls, and knits. You don't want an unhappy ending like this.
The WIP is the back of a baby sweater for my upcoming grandson.* The front is striped in the colors you see between the green. The green is the trim and back color. I am about 1/4 of the way through the armhole. I will be running out of green yarn shortly. (Drat! Another one--this one's at least a little funny. It's not that far off from a Tom Swiftie.)
It's Essential sock yarn from KnitPicks. I am adding the Fair Isle sections to use less green yarn, just in case. You see, I've never run out of yarn on a project before. I didn't use as much less as I thought I would. But then, just before I placed another (fairly rare) KnitPicks order, I "remembered" I had a full skein in addition to the large partial I've been using; It would only be a matter of a deep stash dive to find it. I thought about adding a skein of this to it. But then I reasoned, why add to my stash? "I have way too much yarn already!!!!" shouted that voice in my head. So I didn't add in that ginormous 50 gram skein of really nice, soft, sheeny yarn.
Sometime yesterday I remembered that I've made a pair of infant socks and used it double stranded in 2 previous hats. So, no, I don't have any more. Incidentally, I only remembered when I actually saw one of the hats being worn by its recipient. Now the question is what to do about it. Frog and reknit the back in alternating green stripes with the front colors, rather than Fair Isle? Try to find some other green fingering yarn in my stash that is close enough? (which, indeed, I have, but it is not superwash) Order some from KnitPicks? Try and beg for some on Ravelry and the Knitty board? Go to the LYS and buy some that I will decide later doesn't work?