perplexus.info :: Sequences : Eleven as mandatory divider

Eleven as mandatory divider (Posted on 2021-05-24)

I have found in one of the Russian high-school competitions a relatively easy puzzle & to make it more challenging replaced a certain number by N.
The modified text runs as follows:

Prove that among N sequential positive integers there always exists a number whose s.o.d. is a multiple of 11.
a. Restore N.
b. Now prove the statement.

No Solution Yet Submitted by Ady TZIDON

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re(2): Part a. (but no proof)

| Comment 3 of 5 |

(In reply to re: Part a. (but no proof) by Charlie)

Ha ha!

Well done, Charlie.

I ran my loop to 1,000,000 ; just a bit farther and I would have realized that I was wrong.

Posted by Larry on 2021-05-24 12:34:08

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