John Conway and 15·92

Question

The Economist featured an obituary of John Conway (https://www.economist.com/obituary/2020/04/23/john-conway-died-on-april-11th, may be paywalled) which includes a photograph of him in what I guess is his office at Princeton in the late 80's. On top of his computer monitor is a card with the number 15·92; what does this mean? The use of a "middle-dot" suggests that it is not a decimal number, and it is not a date or time in a commonly-used format. I am aware that Conway was not a "common-user" (as a date it is May 31 of the following year, as a time 28 minutes before five), but why did he find this number sufficiently important to dominate his work environment?

Answer 1

That was his personal record (at the time) for a running computational challenge. Specifically, the challenge was: a computer would generate $10$ dates randomly from the past few hundred years and one had to provide all $10$ days of the week. He did it in $15.92$ seconds. ( Later he was able to get it under $10$ seconds).

See this article for a reference.