Ludwig Ritter von Köchel since undergone revisions. Mozart's works are often referred to by their K-numbers ("cf." opus number); for example, the "Jupiter" symphony, "Symphony No. 41" K. 551. Moreover, Köchel arranged Mozart's works into twenty-four categories, which were used by Breitkopf & Härtel when they published the first complete edition of Mozart's works from 1877 to 1910, a venture partly funded by Köchel. He also catalogued the works of Johann Fux. Ludwig Ritter von Köchel Ludwig Alois Friedrich Ritter von Köchel (; 14 January 1800 – 3 June 1877) was an Austrian musicologist, writer, composer, botanist and publisher. He is best known for
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