The On-Line Encyclopedia of Integer Sequences (OEIS)

The OEIS is supported by the many generous donors to the OEIS Foundation.

Revision History for A046422

(Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
Showing all changes.

A046422

Numbers requiring 2 steps to reach a prime under the prime factor concatenation procedure.
(history; published version)

#9 by N. J. A. Sloane at Sun Aug 11 14:41:31 EDT 2024

LINKS

P. De Geest, <a href="httphttps://www.worldofnumbers.com/topic1.htm">Home Primes</a>

Discussion

Sun Aug 11

14:41

OEIS Server: https://oeis.org/edit/global/2998

#8 by N. J. A. Sloane at Sun Oct 13 23:18:25 EDT 2019

STATUS

proposed

approved

#7 by Jon E. Schoenfield at Sun Oct 13 22:01:37 EDT 2019

STATUS

editing

proposed

#6 by Jon E. Schoenfield at Sun Oct 13 22:01:23 EDT 2019

NAME

Numbers requiring 2 steps needed to reach a prime under the prime factor concatenation procedure.

EXAMPLE

24 = 2^3 * 2*2*3, 2223 = 3^2 * 3*13 * 19, 331319 is prime.

AUTHOR

Patrick De Geest, Jun 15 1998.

STATUS

approved

editing

Discussion

Sun Oct 13

22:01

Jon E. Schoenfield: Edits to Name okay?

#5 by Charles R Greathouse IV at Fri Aug 24 10:48:00 EDT 2012

AUTHOR

_Patrick De Geest (pdg(AT)worldofnumbers.com), _, Jun 15 1998.

Discussion

Fri Aug 24

10:48

OEIS Server: https://oeis.org/edit/global/1824

#4 by Russ Cox at Fri Mar 30 17:28:17 EDT 2012

EXTENSIONS

Edited by _Charles R Greathouse IV (charles.greathouse(AT)case.edu), _, Apr 28 2010

Discussion

Fri Mar 30

17:28

OEIS Server: https://oeis.org/edit/global/147

#3 by N. J. A. Sloane at Tue Jun 01 03:00:00 EDT 2010

OFFSET

0,1,1

EXAMPLE

38 24 = 2^3 * 3, 2223 = 3^2 * 13 * 19 -> 219 = 3*73 and 373 , 331319 is prime.

KEYWORD

nonn,base,new

EXTENSIONS

Edited by Charles R Greathouse IV (charles.greathouse(AT)case.edu), Apr 28 2010

#2 by N. J. A. Sloane at Fri May 16 03:00:00 EDT 2003

LINKS

P. De Geest, <a href="http://www.pingworldofnumbers.be/~ping6758com/topic1.htm">SourceHome Primes</a>

KEYWORD

nonn,new

nonn

AUTHOR

Patrick De Geest (Patrick.DeGeest@pingpdg(AT)worldofnumbers.becom), June Jun 15 1998.

#1 by N. J. A. Sloane at Sat Dec 11 03:00:00 EST 1999

NAME

2 steps needed to reach a prime under prime factor concatenation procedure.

DATA

4, 9, 24, 30, 32, 36, 38, 42, 50, 55, 57, 60, 68, 74, 75, 88, 92, 94, 99, 102, 106, 108, 110, 122, 134, 140, 155, 158, 174, 194, 206, 209, 215, 231, 244, 254, 272, 280, 287, 298, 299, 306, 314, 323, 332, 334, 346, 351, 362, 365, 371, 374, 398, 413, 415, 417

OFFSET

0,1

LINKS

<a href="http://www.ping.be/~ping6758/topic1.htm">Source</a>

EXAMPLE

38 = 2*19 -> 219 = 3*73 and 373 is prime.

CROSSREFS

Cf. A037271, A046411.

KEYWORD

nonn

AUTHOR

Patrick De Geest (Patrick.DeGeest@ping.be), June 1998.

STATUS

approved