Article View: sci.crypt
Article #3554Spacing of Prime Numbers
From: johns
Date: Tue, 28 Apr 1987 19:48
Date: Tue, 28 Apr 1987 19:48
39 lines
1895 bytes
1895 bytes
This may not be news to readers of this group, but I thought the follow-
ing tidbit was interesting.
The May issue of DISCOVER magazine presented a cute problem as
part of its brain teaser section on the last page of the magazine. The
question was (I'm paraphrasing it):
Prove there is a sequence of at least one million
consecutive integers, none of whom are prime.
The answer is surprisingly easy:
----------------------(Spoiler Follows)----------------------------
Let M = (3 * 4 * 5 * ... * 1,000,003) = (1,000,003!) / 2
Then the consecutive sequence of one million integers consisting of:
M3 = (M + 3) (that's "M sub three", not "M times three")
M4 = (M + 4)
M5 = (M + 5)
... etc, etc up to M1000003 = (M + 1,000,003)
contains no primes because 3 is a factor of M3, 4 is a factor of M4, and
so on, and so on... until 1000003 is a factor of M1000003.
I had always guessed primes were more closely spaced than that.
(But then, number theory is not my forte.)
BTW, DISCOVER is a great magazine for explaining technical
subjects using language almost anyone can understand. It's usually good
reading for subjects outside one's specialty. (Such as number theory,
for me).
John Stice.............
usual disclaimers apply..... etc.
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Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: arc1-ca.pugleaf.net!utzoo!utgpu!water!watmath!clyde!rutgers!mit-eddie!uw-beaver!tikal!phred!johns From: johns@phred.UUCP Newsgroups: sci.crypt Subject: Spacing of Prime Numbers Message-ID: <1392@phred.UUCP> Date: Tue, 28-Apr-87 15:48:56 EDT Article-I.D.: phred.1392 Posted: Tue Apr 28 15:48:56 1987 Date-Received: Fri, 1-May-87 01:00:01 EDT Organization: Physio Control Corp., Seattle WA Lines: 39 Keywords: Primes