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Binary Primes (Posted on 2004-02-18)

How many primes, written in usual base 10, have digits that are alternating 1s and 0s, beginning and ending with one?

For example (not necessarily prime):
1, 101, 10101, ...

See The Solution Submitted by Aaron

Rating: 3.5000 (2 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)

OK I swear this is the last time!

| Comment 9 of 13 |

If you have even digit numbers like 1010 and 101010 they are obviously divisible by 10.

Posted by Mitch Mullings on 2004-02-22 21:01:21

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