The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A281168 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A281168

Numbers k such that (25*10^k + 71)/3 is prime.
(history; published version)

#14 by Michael De Vlieger at Mon Jun 10 23:37:08 EDT 2024

STATUS

proposed

approved

#13 by Jon E. Schoenfield at Mon Jun 10 21:36:52 EDT 2024

STATUS

editing

proposed

#12 by Jon E. Schoenfield at Mon Jun 10 21:36:49 EDT 2024

COMMENTS

For k > 1, numbers k such that the digit 8 followed by k-2 occurrences of the digit 3 followed by the digits 57 is prime (see Example section).

LINKS

Makoto Kamada, <a href="https://stdkmd.net/nrr/prime/primedifficultyprime_difficulty.txt">Search for 83w57</a>.

EXAMPLE

Initial terms and primes associated primes:

STATUS

approved

editing

#11 by N. J. A. Sloane at Sat Sep 21 14:33:12 EDT 2019

STATUS

reviewed

approved

#10 by Joerg Arndt at Sat Sep 21 10:38:11 EDT 2019

STATUS

proposed

reviewed

#9 by Robert Price at Sat Sep 21 10:02:33 EDT 2019

STATUS

editing

proposed

#8 by Robert Price at Sat Sep 21 10:02:28 EDT 2019

COMMENTS

a(26) > 2*10^5.

LINKS

Makoto Kamada, <a href="https://stdkmd.net/nrr/prime/primedifficulty.txt">Search for 83w57.</a>.

STATUS

approved

editing

#7 by Charles R Greathouse IV at Thu Jan 17 13:44:09 EST 2019

LINKS

Makoto Kamada, <a href="httphttps://stdkmd.comnet/nrr">Factorization of near-repdigit-related numbers</a>.

Makoto Kamada, <a href="httphttps://stdkmd.comnet/nrr/prime/primedifficulty.txt">Search for 83w57.</a>

Discussion

Thu Jan 17

13:44

OEIS Server: https://oeis.org/edit/global/2791

#6 by N. J. A. Sloane at Mon Jan 16 14:10:49 EST 2017

STATUS

proposed

approved

#5 by Robert Price at Mon Jan 16 10:33:19 EST 2017

STATUS

editing

proposed