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Revision History for A020198

(Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
Showing entries 1-10 | older changes

A020198

Pseudoprimes to base 70.
(history; published version)

#22 by Charles R Greathouse IV at Fri Jun 12 10:52:49 EDT 2015

STATUS

editing

approved

#21 by Charles R Greathouse IV at Fri Jun 12 10:52:47 EDT 2015

PROG

(PARI) forcomposite(n=4, 1e6, if(Mod(70, n)^(n-1)==1, print1(n", "))) \\ Charles R Greathouse IV, Jun 12 2015

STATUS

reviewed

editing

#20 by Joerg Arndt at Fri Jun 12 10:48:48 EDT 2015

STATUS

proposed

reviewed

#19 by Alois P. Heinz at Fri Jun 12 10:48:18 EDT 2015

STATUS

editing

proposed

#18 by Alois P. Heinz at Fri Jun 12 10:47:05 EDT 2015

MATHEMATICA

base = 70; 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 *)

STATUS

proposed

editing

Discussion

Fri Jun 12

10:48

Alois P. Heinz: We can have more than one program.

#17 by Alonso del Arte at Fri Jun 12 10:18:59 EDT 2015

STATUS

editing

proposed

#16 by Alonso del Arte at Fri Jun 12 10:17:33 EDT 2015

COMMENTS

Composite numbers n such that 70^(n-1) == 1 (mod n). [From - _Michel Lagneau, _, Feb 18 2012]

MATHEMATICA

base = 70; 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[10^4], Not[PrimeQ[#]] && PowerMod[70, # - 1, #] == 1 &] (* Alonso del Arte, Jun 12 2015, based on Farideh Firoozbakht's program for A005939 *)

STATUS

approved

editing

Discussion

Fri Jun 12

10:18

Alonso del Arte: Never thought I'd have to replace one of Tony's Mathematica programs. But if there's a simpler way to accomplish something without AppendTo, then the AppendTo program has got to go.

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

MATHEMATICA

base = 70; 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

#13 by T. D. Noe at Tue Feb 21 15:04:36 EST 2012

STATUS

editing

approved