“…If D = −4n, then [1, 0, n] is the principal form. Finally, we say that an integer m is represented by the genus G if it is represented by at least one class in G. For example, if n = 14 (and thus D = −56 and h(D) = 4), then we have two genera G 1 and G 2 where, say, (the class of) [1,0,14] and [2,0,7] belong to G 1 while [3, −2, 5] and [3,2,5] belong to G 2 .…”