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Post by Admin on Mar 19, 2019 6:33:14 GMT
That's impressive, mate, but you misread my post. "what's the first 47 digit prime number you would encounter?" The first single number that is both a prime and consists of 47 digits... It still was entertaining to see my speed and accuracy. It seems I got only 1 wrong in 47 and missed about 4. The wrong one that I got was 207. The first prime that I missed was 89. Fun fact: If the sum of the single digits of any number is divisible by three, then so is the original number. 2+0+7=9 9 is divisible by three, therefore so is 207.
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Post by ant-mac on Mar 19, 2019 6:38:43 GMT
That's impressive, mate, but you misread my post. "what's the first 47 digit prime number you would encounter?" The first single number that is both a prime and consists of 47 digits... It still was entertaining to see my speed and accuracy. It seems I got only 1 wrong in 47 and missed about 4. The wrong one that I got was 207. The first prime that I missed was 89. Yes, I can fully understand the pleasure you might derive from such a mental exercise.
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Post by Aj_June on Mar 19, 2019 6:39:26 GMT
It still was entertaining to see my speed and accuracy. It seems I got only 1 wrong in 47 and missed about 4. The wrong one that I got was 207. The first prime that I missed was 89. Fun fact: If the sum of the single digits of any number is divisible by three, then so is the original number. 2+0+7=9 9 is divisible by three, therefore so is 207. Yeah, that was the very divisibility test I was using. I was summing the digits and tested for the sum to divisible by 3. With 5 you know if the number ends in 5 or 0 then only it is divisible.
I seemed to have got tired by end and so counted 207 incorrectly. There is also divisibility test for 11 but I have forgotten it now. Old age is catching with me
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