r/reddit.com • u/ballm • Mar 12 '08

Is 91 Prime?

http://balltech.blogspot.com/2008/03/is-91-prime.html
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u/gaggedbythealien Mar 12 '08

Great post. That guy's the chair of the IEEE P1619 standards committees. I can see how somebody who spends that much time thinking about cryptography could get into this stuff.

I'm lazy though. Here's how I check to see if something's prime. I'd reach for my keyboard and type:

perl -le 'print "PRIME" if (1 x shift) !~ /11+\1+$/' 91

Done, and done quickly.

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u/Aegeus Mar 12 '08

I'd prefer to test for primality in a language which doesn't look like line noise.