Köchel catalogue son's earlier works; Mozart's catalogue of his own compositions (begun in February 1784 with K. 449) allows relatively precise dating of many of his later works. The catalogue included the opening bars of each piece, known as an incipit. Köchel divided the corpus into a main chronology of 626 works, and five appendices ("" in German, abbreviated to "Anh.") The appendices (Anh. I-V) included: Since Köchel published his original catalogue in 1863 (now referred to as K), the dating of Mozart's compositions has been subject to constant revision. Many more pieces have since been found, re-dated, re-attributed and re-numbered, requiring
Stirling numbers of the first kind Stirling numbers of the first kind In mathematics, especially in combinatorics, Stirling numbers of the first kind arise in the study of permutations. In particular, the Stirling numbers of the first kind count permutations according to their number of cycles (counting fixed points as cycles of length one). The original definition of Stirling numbers of the first kind was algebraic. These numbers, usually written "s"("n", "k"), are signed integers whose sign, positive or negative, depends on the parity of "n" − "k". Afterwards, the absolute values of these numbers, |"s"("n", "k")|, which are known as unsigned Stirling numbers of the