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74 arithmetic/digits/prime/prefix.one.p




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This article is from the Puzzles FAQ, by Chris Cole chris@questrel.questrel.com and Matthew Daly mwdaly@pobox.com with numerous contributions by others.

74 arithmetic/digits/prime/prefix.one.p


2 is prime, but 12, 22, ..., 92 are not. Similarly, 5 is prime
whereas 15, 25, ..., 95 are not. What is the next prime number
which is composite when any digit is prefixed?

arithmetic/digits/prime/prefix.one.s

149

 

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