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-   -   OEIS sequence A088782 (https://www.mersenneforum.org/showthread.php?t=23308)

 sweety439 2018-04-29 19:55

OEIS sequence A088782

This sequence is in fact the reversed Sierpinski problem with k=10, according to the thread [URL="http://mersenneforum.org/showthread.php?t=10354&page=8"]http://mersenneforum.org/showthread.php?t=10354&page=8[/URL], this sequence can be extended to a(184), and a(185) is > 10^6 due to the Sierpinski base 185 problem, and the related sequence A088783 can be added another term 177, since a prime 10*173^264234 is known.

Also the sequence A119624 (the reversed Sierpinski problem with k=2) can be extended to a(364), and A119591 (the reversed Riesel problem with k=2) can be extended to a(580).

 JeppeSN 2018-04-30 06:43

You are absolutely right. This is about primes 10*b^t + 1 for fixed b when t runs from 1 through infinity. You call it [I]reversed[/I] Sierpiński?

I am extending [URL="https://oeis.org/A088783"]A088783[/URL] as you suggested (see "History" of the entry until edits are approved).

/JeppeSN

 sweety439 2018-04-30 14:05

[QUOTE=JeppeSN;486632]You are absolutely right. This is about primes 10*b^t + 1 for fixed b when t runs from 1 through infinity. You call it [I]reversed[/I] Sierpiński?

I am extending [URL="https://oeis.org/A088783"]A088783[/URL] as you suggested (see "History" of the entry until edits are approved).

/JeppeSN[/QUOTE]

Not just I called, please see A263500.

You can also extend A088782 to n=184, A119624 to n=364, A253178 to n=242 and A119591 to n=580 (by create a b-file).

 sweety439 2018-04-30 14:09

Besides, you can create a-files for these sequences for the status (with some unknown terms, you can use "?" for them and give the test limits) to n=1000.

 JeppeSN 2018-04-30 15:21

OK, it is a reference to [URL="https://scholar.rose-hulman.edu/rhumj/vol9/iss2/4"]Krywaruczenko, Daniel (2008) "A Reverse Sierpinski Number Problem," [I]Rose-Hulman Undergraduate Mathematics Journal[/I]: Vol. 9 : Iss. 2 , Article 4.[/URL] I will fix the link to that paper in OEIS. /JeppeSN

 sweety439 2018-04-30 19:16

[QUOTE=sweety439;486658]Besides, you can create a-files for these sequences for the status (with some unknown terms, you can use "?" for them and give the test limits) to n=1000.[/QUOTE]

Also write a reference to CRUS page.

 sweety439 2018-04-30 19:17

[QUOTE=JeppeSN;486663]OK, it is a reference to [URL="https://scholar.rose-hulman.edu/rhumj/vol9/iss2/4"]Krywaruczenko, Daniel (2008) "A Reverse Sierpinski Number Problem," [I]Rose-Hulman Undergraduate Mathematics Journal[/I]: Vol. 9 : Iss. 2 , Article 4.[/URL] I will fix the link to that paper in OEIS. /JeppeSN[/QUOTE]

For A263500, I found a(n) for all n<=64 in the post [URL="http://mersenneforum.org/showpost.php?p=451256&postcount=2"]http://mersenneforum.org/showpost.php?p=451256&postcount=2[/URL].

 JeppeSN 2018-04-30 22:52

Sweety439, I think you should update those OEIS entries yourself. /JeppeSN

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