Yes, Ingrid has hit it right on the head! I am working right now on a Lion Homespun triangle shawl and the pattern is exactly that....k1, yo, knit to end. This increases by 1 stitch each row. Then just keep going until it is wide enough to wrap around you, and voila!
I am using size 15 needles so I think 17 or 19 would be fine with a nice yarn.