The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A020196 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A020196

Pseudoprimes to base 68.
(history; published version)

#23 by Bruno Berselli at Mon Jun 25 03:47:48 EDT 2018

STATUS

reviewed

approved

#22 by Joerg Arndt at Sun Jun 17 02:03:41 EDT 2018

STATUS

proposed

reviewed

#21 by Alonso del Arte at Sun Jun 17 01:22:46 EDT 2018

STATUS

editing

proposed

Discussion

Sun Jun 17

02:03

Joerg Arndt: Indeed.

#20 by Alonso del Arte at Sun Jun 17 01:20:24 EDT 2018

MATHEMATICA

base = 68; t = {}; n = 1; While[Length[t] < 100, n++; If[! PrimeQ[n] && PowerMod[base, n - 1, n] == 1, AppendTo[t, n]]]; t (* T. D. Noe, Feb 21 2012 *)

max = 5000; Select[Complement[Range[max], Prime[Range[PrimePi[max]]]], PowerMod[68, # - 1, #] == 1 &] (* _Alonso del Arte_, Jun 17 2018 *)

Discussion

Sun Jun 17

01:22

Alonso del Arte: There's a time and a place for AppendTo, but, in my opinion, this is not it.

#19 by Alonso del Arte at Wed Jun 13 23:03:09 EDT 2018

MATHEMATICA

base = 68; t = {}; n = 1; While[Length[t] < 100, n++; If[! PrimeQ[n] && PowerMod[base, n - 1, n] == 1, AppendTo[t, n]]]; t (* T. D. Noe, Feb 21 2012 *)

Select[Range[

STATUS

approved

editing

#18 by Susanna Cuyler at Wed Jun 13 09:17:31 EDT 2018

STATUS

proposed

approved

#17 by Jon E. Schoenfield at Tue Jun 12 23:13:42 EDT 2018

STATUS

editing

proposed

#16 by Jon E. Schoenfield at Tue Jun 12 23:13:39 EDT 2018

COMMENTS

Composite numbers n such that 68^(n-1) == 1 (mod n). [From - _Michel Lagneau, _, Feb 18 2012]

STATUS

approved

editing

#15 by Charles R Greathouse IV at Sun Aug 03 14:01:12 EDT 2014

MATHEMATICA

base = 68; t = {}; n = 1; While[Length[t] < 100, n++; If[! PrimeQ[n] && PowerMod[base, n-1, n] == 1, AppendTo[t, n]]]; t (* _T. D. Noe, _, Feb 21 2012 *)

Discussion

Sun Aug 03

14:01

OEIS Server: https://oeis.org/edit/global/2267

#14 by Russ Cox at Fri Mar 30 18:35:12 EDT 2012

AUTHOR

_David W. Wilson (davidwwilson(AT)comcast.net)_

Discussion

Fri Mar 30

18:35

OEIS Server: https://oeis.org/edit/global/202