The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A176902 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
Showing all changes.

A176902

Primes p such that p-1 and p+1 are both non-semiprime.
(history; published version)

#6 by N. J. A. Sloane at Thu Dec 05 21:00:35 EST 2019

STATUS

editing

approved

#5 by N. J. A. Sloane at Thu Dec 05 21:00:32 EST 2019

COMMENTS

Two 2 together with A060254.

STATUS

approved

editing

#4 by Russ Cox at Fri Mar 30 18:52:40 EDT 2012

AUTHOR

_Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), _, Apr 28 2010

Discussion

Fri Mar 30

18:52

OEIS Server: https://oeis.org/edit/global/257

#3 by Russ Cox at Fri Mar 30 17:40:23 EDT 2012

EXTENSIONS

Corrected (233, 239 inserted, 279 and 289 replaced by 379 and 389) by _R. J. Mathar (mathar(AT)strw.leidenuniv.nl), _, Aug 12 2010

Discussion

Fri Mar 30

17:40

OEIS Server: https://oeis.org/edit/global/190

#2 by N. J. A. Sloane at Fri Aug 27 03:00:00 EDT 2010

DATA

2, 17, 19, 29, 31, 41, 43, 53, 67, 71, 79, 89, 97, 101, 103, 109, 113, 127, 131, 137, 139, 149, 151, 163, 173, 181, 191, 197, 199, 211, 223, 229, 233, 239, 241, 251, 257, 269, 271, 281, 283, 293, 307, 311, 317, 331, 337, 349, 353, 367, 373, 279, 289, 379, 389, 401, 409, 419, 431

EXTENSIONS

Corrected (233, 239 inserted, 279 and 289 replaced by 379 and 389) by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 12 2010

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

NAME

Primes p such that p-1 and p+1 are both non-semiprime.

DATA

2, 17, 19, 29, 31, 41, 43, 53, 67, 71, 79, 89, 97, 101, 103, 109, 113, 127, 131, 137, 139, 149, 151, 163, 173, 181, 191, 197, 199, 211, 223, 229, 241, 251, 257, 269, 271, 281, 283, 293, 307, 311, 317, 331, 337, 349, 353, 367, 373, 279, 289, 401, 409, 419, 431

OFFSET

1,1

COMMENTS

Two together with A060254.

FORMULA

a(n+1)=A060254(n)=A167915(n+1).

EXAMPLE

a(1)=2 because 2-1=1=non-semiprime and 2+1=3=non-semiprime.

KEYWORD

nonn,new

AUTHOR

Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Apr 28 2010

STATUS

approved