What was the story Asimov pulled from circulation over accidental similarities?

Question

In Asimov's Galaxy, the Good Doctor writes:

But I haven’t read every story ever written and many that I have read, I have completely forgotten, at least consciously. What if I duplicate important elements of stories I have never read or have forgotten? It’s possible. I once wrote a short-short which ended with a certain dramatic climax in the last sentence. Eventually, I received a letter from another writer whose story had been published before I wrote my story and who had made use of the same dramatic climax in his last sentence. What's more, I had his story in an anthology in my library. I did not remember reading it, but I had had the opportunity to do so. The two stories, except for the climaxes, were completely different, but I promptly wrote the other author and told him that although he had my word that there was no conscious imitation, I would withdraw the story from circulation and it would never again appear in any anthology, any collection, any form whatever—and it never has.

Presumably, as almost all of the rest of Asimov's science fiction output has been anthologised in some form or another, it should be possible to deduce what this story is. What is the missing story? And, if it can be ascertained, what is the other story with a similar ending?

Answer 1

This is the short story Question (not to be confused with his more famous short story The Last Question).

From the wikipedia summary:

The story concerns two technicians who are servicing Multivac, and their argument over whether or not the machine is truly intelligent and able to think. Multivac, however, supplies the answer on its own.

The story concludes with Multivac asking itself "WHO AM I... WHO AM I... WHO AM I ..."

After the reprint, another author, Robert Sherman Townes, noticed the climax in the last sentence was very similar to one of his own stories, "Problem for Emmy" (Startling Stories, June 1952), and wrote to Asimov about it. After searching in his library, Asimov did find the original story and, although he did not recall having read it, admitted that the endings were pretty similar.

He then replied to Townes, apologizing and promising the story would never again be published, and it never was. Asimov mentioned "Question" in an editorial called "Plagiarism" which appeared in the August 1985 issue of Asimov's Science Fiction (although he did not mention Townes' name or the title of either story). "Plagiarism" was reprinted in Asimov's collection Gold (1995).

Townes story also deals with a giant computer - the "Manndenker-Goldemacher Electronic Calculator Implemented Model M-VII", known for short as Emmy - which appears to become self-aware. The story ends with Emmy chanting times-tables to itself, and endlessly printing out "WHO AM I WHO AM I WHO AM I".

Asimov's original story is available here, and Townes' from this edition of Startling Stories.