Köchel catalogue Köchel catalogue The Köchel catalogue () is a chronological catalogue of compositions by Wolfgang Amadeus Mozart, originally created by Ludwig von Köchel, in which the entries are abbreviated "K." and "KV". The numbers of the Köchel catalogue reflect the continuing establishment of a complete chronology of Mozart's works, and provide a shorthand reference to the compositions. According to Köchel's counting, "Requiem in D minor" is the 626th piece Mozart composed, thus is designated either "K. 626" or "KV 626"; however, his original catalogue (1862) of Mozart has been twice revised, and some works have had three KV. numbers, e.g. Mozart's
Stirling numbers of the second kind for Stirling numbers of the second kind. The brace notation formula_2 was used by Imanuel Marx and Antonio Salmeri in 1962 for variants of these numbers. This led Knuth to use it, as shown here, in the first volume of "The Art of Computer Programming" (1968). However, according to the third edition of "The Art of Computer Programming", this notation was also used earlier by Jovan Karamata in 1935. The notation "S"("n", "k") was used by Richard Stanley in his book "Enumerative Combinatorics". Since the Stirling number formula_15 counts set partitions of an "n"-element set into "k" parts, the sum