The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A225575

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A225575

Primes p such that if q is the next prime after p then the concatenation of p with q and the concatenation of q with p are both primes.
(history; published version)

#33 by Charles R Greathouse IV at Thu Sep 08 08:46:05 EDT 2022

PROG

(MAGMAMagma) conc:=func<a, b|a*10^(#Intseq(b))+b>; [p:p in PrimesUpTo(17000)| IsPrime(conc(p, (NextPrime(p)))) and IsPrime(conc(NextPrime(p), p))]; // Marius A. Burtea, Jan 25 2020

Discussion

Thu Sep 08

08:46

OEIS Server: https://oeis.org/edit/global/2944

#32 by OEIS Server at Wed Feb 19 09:33:16 EST 2020

LINKS

Marius A. Burtea, <a href="/A225575/b225575_1.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..250 from Paolo P. Lava)

#31 by Alois P. Heinz at Wed Feb 19 09:33:16 EST 2020

STATUS

proposed

approved

Discussion

Wed Feb 19

09:33

OEIS Server: Installed new b-file as b225575.txt.  Old b-file is now b225575_1.txt.

#30 by Alois P. Heinz at Wed Feb 19 09:32:52 EST 2020

STATUS

editing

proposed

#29 by Alois P. Heinz at Wed Feb 19 09:32:47 EST 2020

DATA

199, 233, 257, 353, 523, 653, 971, 1973, 2333, 3259, 3637, 3761, 4283, 4993, 5927, 6353, 6529, 6563, 7907, 8831, 9293, 9851, 10711, 10861, 11731, 13037, 13177, 13681, 15241, 16381, 16693, 16931, 18341, 18899, 19577, 21787, 23857, 24071, 28621, 31657, 32911

STATUS

reviewed

editing

#28 by Michel Marcus at Wed Feb 19 09:22:25 EST 2020

STATUS

proposed

reviewed

#27 by Jon E. Schoenfield at Sat Jan 25 13:42:26 EST 2020

STATUS

editing

proposed

#26 by Jon E. Schoenfield at Sat Jan 25 13:42:22 EST 2020

COMMENTS

This sequence was suggested by Puzzle 687 at Prime Puzzles (see Links).

In general, q-p == 0 (mod 6). - Zak Seidov, May 11 2013

LINKS

Marius A. Burtea, <a href="/A225575/b225575_1.txt">Table of n, a(n) for n = 1..10000</a> (terms 1 - ..250 from Paolo. P. Lava.)

STATUS

proposed

editing

#25 by Michel Marcus at Sat Jan 25 09:15:03 EST 2020

STATUS

editing

proposed

#24 by Michel Marcus at Sat Jan 25 09:15:00 EST 2020

LINKS

Carlos Rivera, <a href="http://www.primepuzzles.net/puzzles/puzz_687.htm">Puzzle 687: 17769643</a>, The Prime Puzzles & Problems and PuzzlesConnection.

STATUS

proposed

editing