Here is a ton of data.... though I did not see A number mentioned specifically. http://www.haynesintl.com/pdf/h2019.pdf Last page has phone numbers for the Haynes folks... They for sure can tell you.
A number in regards to what? If its an ASTM spec it will be a B number, since C22 is non ferrous. And there would be several of them depending upon the application and material form desired.