The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A006521 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A006521

Numbers n such that n divides 2^n + 1.
(history; published version)

#88 by Charles R Greathouse IV at Thu Sep 08 08:44:35 EDT 2022

PROG

(MAGMAMagma) [n: n in [1..6*10^5] | (2^n+1) mod n eq 0 ]; // Vincenzo Librandi, Dec 14 2018

Discussion

Thu Sep 08

08:44

OEIS Server: https://oeis.org/edit/global/2944

#87 by Michel Marcus at Fri Apr 17 04:31:21 EDT 2020

STATUS

reviewed

approved

#86 by Joerg Arndt at Fri Apr 17 04:30:49 EDT 2020

STATUS

proposed

reviewed

#85 by F. Chapoton at Thu Apr 16 04:34:46 EDT 2020

STATUS

editing

proposed

#84 by F. Chapoton at Thu Apr 16 04:34:37 EDT 2020

PROG

(PARI) for(n=1, 10^9, 6, if(Mod(2, n)^n==-1, print1(n, ", "))); \\ Joerg Arndt, Nov 30 2014

STATUS

approved

editing

Discussion

Thu Apr 16

04:34

F. Chapoton: shorter bound for pari code

#83 by Alois P. Heinz at Fri Mar 20 19:35:23 EDT 2020

STATUS

editing

approved

#82 by Alois P. Heinz at Fri Mar 20 19:00:58 EDT 2020

CROSSREFS

Column k=2 of A333429.

STATUS

approved

editing

#81 by Alois P. Heinz at Tue Oct 08 15:43:34 EDT 2019

STATUS

editing

approved

#80 by Alois P. Heinz at Tue Oct 08 15:42:26 EDT 2019

CROSSREFS

Solutions to k^m == k-1 (mod m): 1 (k = 1), this sequence (k = 2), A015973 (k = 3), A327840 (k = 4), A327893 A123047 (k = 5), A327943 (k = 6), A328033 (k = 7).

STATUS

approved

editing

#79 by N. J. A. Sloane at Mon Oct 07 14:27:25 EDT 2019

STATUS

proposed

approved