Most entrelac patterns are constructed the same way, differing only with how many sts used and some may start with the WS instead of RS first.
Yes you do repeat row 23 on each triangle; the k13 includes the 2 sts that begin the next triangle. That takes the place of row 1 which is why you should be repeating 2-22. And actually, I think it should say "repeat Rows 2-23, 10 times and Rows 2-22 once more." that way you end on a purl row and will be ready to go to the next section - a side triangle.
sue- knitting heretic