By truncating the polynomials we can focus on the case that the
words in question have length no more than 30. By evaluating
w to be 1, we count the words (we call these words strings).
However, in the chemical application,
we can allow for the 19 possible amino acids which may occur when a W is
present by putting w=19 (we call these words sequences).
We let 
be the polynomial which enumerates all words satisfying
conditions (i), (ii) and (iii) and involve m copies
of B, and are truncated to allow for the
total length 
condition (the escargot polynomials).
Let 
be the polynomials of inaccessibility, which are defined
in the same way, save that conditions (iv) and (v) are also imposed.