Listed in the index of Douglas Hofstadter's "Gödel, Escher, Bach: An Eternal Golden Braid". The end of the "Prelude..." dialogue has statements made by Achilles and TTortoise, while the start of the "..Ant Fugue" dialogue has quotes by Achilles, CCrab and Achilles. Taking the capitalised letters reveals ATTACCA. Taking the definition from Websters 1913, the meaning is clear.
Also, if you look on the twenty-sixth line of the base sequence for the chromosome of bacteriophage φ174, and the 54th letter from the right (which is an A), and read from right to left, you also get ATTACCA. I have no idea what this means, but this page is also listed in the index.