I was sad to learn that Herbert Wilf died yesterday. Long-time readers of this blog may remember him as one of the discoverers of the Calkin-Wilf tree, which I wrote about in a ten-part series of posts (1, 2, 3, 4, 5, 6, 7, 8, 9, 10).
He also wrote generatingfunctionology, a textbook about generating functions, a topic near and dear to my heart (which I hope to write about here someday).
Although he was an emeritus professor at the University of Pennsylvania (where I am currently doing my PhD) I sadly never got a chance to meet him.
He was my professor for calculus 240 and 241 back in 1979-1980. One of my favorite teachers at Penn. I have fond memories of his lectures.