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Old 2021-09-15, 11:19   #265
paulunderwood
 
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Quote:
Originally Posted by sweety439 View Post
https://primes.utm.edu/primes/status.php

id 132704 and 132705 are palindromes.
No they are not Reversing the digits does not give the same number.

https://primes.utm.edu/primes/page.php?id=132715 is a palindrome. Congrats Serge and Ryan.

UTM's Prime Pages parser calculated the decimal digits as 1234568

Last fiddled with by paulunderwood on 2021-09-15 at 11:45
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Old 2021-09-15, 16:06   #266
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Quote:
Originally Posted by paulunderwood View Post
UTM's Prime Pages parser calculated the decimal digits as 1234568
Prof.Caldwell's calculator had insufficient precision. I'll drop him a note. It is, of course, 1234567.

All palindromes of even length (except 11) are composite!
Hint: they are divisible by 11
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Old 2021-09-15, 18:17   #267
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Quote:
Originally Posted by paulunderwood View Post
I am looking forward to its revelation. The largest palindrome before this one had 490,001 digits. So 1,234,567 digits is quite amazing considering its crunching is done with generic modular reduction.
Wow! A megaprime palindrome. And one with more than twice the digits than the previous one!

I have to see it to believe it!
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Old 2021-09-15, 21:52   #268
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Cool

When I was already way into sieving, I thought that I should have picked 1234321 decimal digits length

But it turned out good. With 1234567 digits' dataset the hit came, statistically speaking, very! early. So it was lucky.
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Old 2021-09-21, 00:39   #269
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The prof has been busy. He fixed the palindrome length and puzzle-peter's arithmetic progression, which comes second on table two of https://primes.utm.edu/top20/page.php?id=14.

Hint: An AP9 could be quite easy to find to make it to the top of table two. For the AP8, I wrote my own GWNUM code which was 15% faster, I think mainly by dropping repetitive evaluations of the primorial coefficient. I'd willing to share it with any interested parties.

Last fiddled with by paulunderwood on 2021-09-21 at 00:41
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Old 2021-09-21, 01:30   #270
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Good! Excellent!
Even Kamada-san wrote to him and cc:'d me (as if I could help ).

But it is fixed now, cool beans.
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Old 2021-09-22, 10:07   #271
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Quote:
Originally Posted by Batalov View Post
When I was already way into sieving, I thought that I should have picked 1234321 decimal digits length

But it turned out good. With 1234567 digits' dataset the hit came, statistically speaking, very! early. So it was lucky.

So if it is not secret how many candidates was tested before prime appear?
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Old 2021-09-22, 12:51   #272
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Originally Posted by pepi37 View Post
So if it is not secret how many candidates was tested before prime appear?
About 18,000 of the ~316K inputs that Serge originally sent me.

P.S. (S.B.) - the exact row number for the hit was 13,239th
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Old 2021-09-22, 20:54   #273
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Quote:
Originally Posted by ryanp View Post
About 18,000 of the ~316K inputs that Serge originally sent me.

P.S. (S.B.) - the exact row number for the hit was 13,239th

13239-th: small number of candidates for such prime. Very lucky hit :)
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Old 2021-09-25, 01:14   #274
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This is an incredible result! https://primes.utm.edu/primes/page.php?id=132738



But now we have two different record arithmetic progression of 3 elements of 884,748 and 807,954 digits. the other one being. https://primes.utm.edu/primes/page.php?id=132738



Still these AP-3 is truly impressive as the number of digits either is over 70% more than the previous one which was 406,437 digits.




Congratulations to Ryan and Serge.
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Old 2021-09-27, 20:59   #275
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Congrats to James Winskill for the mega primorial prime: 3267113# - 1 (1,418,398 decimal digits).

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