4,3,5,4,3,6,8,7,7,__

Note : Think about the number of letters in some 'Numerical' (but English) words.

hi,

  Well I managed to get the right answer (8) but derived it in a different way, still using the idea of word sequencing. First of all, the most obvious thing to note is that the sequence in question must grow larger, so from this alone we can eliminate a lot of the possibilities for the numbers in the pseudo-sequence I'm about to derive. The "pseudo-sequence" I got to solve this was {4, 6, 7, 9, 10, 12, 13, 15, 16, _} and we have to get the '_' and then decode it to the original sequence. (You can verify that these numbers match the corresponding number of letters in the words: i.e. [4]=4 letters=4, [6]=3 letters=3, and so forth. Clearly by logic this sequence would work just as well for the problem as the composite number solution posted. Also, it is easy enough to see the pattern in this sequence: each pair of consecutive numbers is followed by 2+the previous number and so forth. Filling in the _ you get 18, and 18 is 8 letters and hence the answer is 8.