You're on the right track

Your code:
close, but list.length is always going to be the same. How about (last - first)? You're using first and last as indexes of your list, so the difference between the two should give you the number of elements you are searching.
Then you just need to figure out how to do a sequential search of that subset of your list. Is it possible for you to change the sequential search function to take first and last as parameters along with the key? That way seqSearch() will know what range of your list to search (where to start and where to stop).
Plus, you're right that you need something else along with that
test to see if the remaining length is less than 15. You need to call seqSearch(), and then return whatever value it gives you. So to make it easier, just put it in one line:
something like that...
[EDIT: Sorry Ricky, I pretty much copied what you said without realizing.]
[ April 03, 2007: Message edited by: Eric Daly ]