The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A005938 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A005938

Pseudoprimes to base 7.
(history; published version)

#44 by Peter Luschny at Fri Jun 25 12:09:21 EDT 2021

STATUS

reviewed

approved

#43 by Michel Marcus at Fri Jun 25 11:56:37 EDT 2021

STATUS

proposed

reviewed

#42 by Michael S. Branicky at Fri Jun 25 10:52:11 EDT 2021

STATUS

editing

proposed

#41 by Michael S. Branicky at Fri Jun 25 10:45:48 EDT 2021

DATA

6, 25, 325, 561, 703, 817, 1105, 1825, 2101, 2353, 2465, 3277, 4525, 4825, 6697, 8321, 10225, 10585, 10621, 11041, 11521, 12025, 13665, 14089, 16725, 16806, 18721, 19345, 20197, 20417, 20425, 22945, 25829, 26419, 29234, 29341, 29857, 29891, 30025, 30811, 33227

#40 by Michael S. Branicky at Fri Jun 25 10:43:27 EDT 2021

PROG

(Python)

from sympy import isprime

def ok(n): return pow(7, n-1, n) == 1 and not isprime(n)

print(list(filter(ok, range(1, 34000)))) # Michael S. Branicky, Jun 25 2021

STATUS

approved

editing

#39 by Joerg Arndt at Mon Oct 16 01:58:06 EDT 2017

STATUS

reviewed

approved

#38 by Michel Marcus at Sun Oct 15 23:09:38 EDT 2017

STATUS

proposed

reviewed

#37 by Rachel Barnett at Sun Oct 15 22:16:04 EDT 2017

STATUS

editing

proposed

#36 by Rachel Barnett at Sun Oct 15 22:16:00 EDT 2017

LINKS

C. Pomerance & N. J. A. Sloane, <a href="/A001567/a001567_4.pdf">Correspondence, 1991</a>

STATUS

approved

editing

#35 by Ray Chandler at Tue Aug 22 09:34:35 EDT 2017

STATUS

editing

approved