In 1971/1972 academic year, I was an undergraduate student at the Hebrew University of Jerusalem and toward the end of the year I wrote a paper about Abel’s sums. I sent it to John Riordan the author of the books “Combinatorial Identities” and “Combinatorial Analysis”.
I received this letter shortly after my 17th birthday, and I was surely very happy to read the sentence “I think you have had a splendid idea”. Here is part of Riordan’s remarks. The full report is here.
It took me some time to revise the paper and get it printed. And here is the report for the second version.
And here is part of Riordan’s second round of remarks. The full report is here.
I was certainly happy to read the following sentence: “I would remark that the result for p = -1 is new and perhaps the simplest derivation of Abel’s result.”
In 1978 I actually visited John Riordan in his office at Rockefeller University, NYC. I remember him as very cheerful and he told me that when his first book appeared he was working at Bell Labs and his managers wanted to talk to him. He was a bit worried that they would not approve of him spending time and effort to write a book in pure mathematics. But actually, they gave him a salary raise!
(If you have a picture of John Riordan, please send me.)
In 1979 the paper appeared.