The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A259136 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A259136

Numbers k such that 4*R_k + 7*10^k + 3 is prime, where R_k = 11...11 is the repunit (A002275) of length k.
(history; published version)

#12 by Joerg Arndt at Thu Jul 08 01:19:38 EDT 2021

STATUS

reviewed

approved

#11 by Joerg Arndt at Thu Jul 08 01:17:45 EDT 2021

STATUS

proposed

reviewed

#10 by Jon E. Schoenfield at Thu Jul 08 01:10:41 EDT 2021

STATUS

editing

proposed

#9 by Jon E. Schoenfield at Thu Jul 08 01:10:39 EDT 2021

COMMENTS

Also, numbers k such that (67*10^nk + 23)/9 is prime.

STATUS

approved

editing

#8 by Charles R Greathouse IV at Thu Jan 17 13:44:08 EST 2019

LINKS

Makoto Kamada, <a href="httphttps://stdkmd.comnet/nrr/abbba.htm">Near-repdigit numbers of the form ABB...BBA</a>.

Makoto Kamada, <a href="httphttps://stdkmd.comnet/nrr/7/74447.htm#prime">Prime numbers of the form 744...447</a>.

Discussion

Thu Jan 17

13:44

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

#7 by Bruno Berselli at Fri Jun 19 13:03:32 EDT 2015

STATUS

editing

approved

#6 by Bruno Berselli at Fri Jun 19 13:03:20 EDT 2015

PROG

(MAGMA) [n: n in [0..500] | IsPrime((67*10^n+23)div 9)]; // Vincenzo Librandi, Jun 19 2015

KEYWORD

nonn,more,hard,nonn,changed

STATUS

proposed

editing

#5 by Vincenzo Librandi at Fri Jun 19 03:07:25 EDT 2015

STATUS

editing

proposed

#4 by Vincenzo Librandi at Fri Jun 19 03:07:18 EDT 2015

PROG

(MAGMA) [n: n in [0..500] | IsPrime((67*10^n+23)div 9)]; // Vincenzo Librandi, Jun 19 2015

STATUS

proposed

editing

#3 by Robert Price at Thu Jun 18 19:22:59 EDT 2015

STATUS

editing

proposed