This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
1 solution
Each alternate number is actually part of a different sequence, so the 2 sequences are 1, 2, 3, 4 and 5, 9, 13, 17. As the next number is following the first sequence, the answer is 5.