Big Book of Knitting Stitch Patterns p. 154
The book says to work k5 together as ssssk: slip each of the next four stitches knitwise, k1, then pass the slipped stitches over. It might not be necessary to make the right effect, though.
1-to-5 increase: work (p1, k1, p1, k1, p1) in next stitch.
Shown with a cast-on count of 17 stitches.