The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A277172

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Showing entries 1-10 | older changes

A277172

Numbers n such that 2^(sigma(n)-n) == 1 (mod n).
(history; published version)

#29 by Charles R Greathouse IV at Sat Oct 15 15:03:56 EDT 2016

STATUS

editing

approved

#28 by Charles R Greathouse IV at Sat Oct 15 15:03:52 EDT 2016

LINKS

Charles R Greathouse IV, <a href="/A277172/b277172.txt">Table of n, a(n) for n = 1..32</a>

STATUS

approved

editing

#27 by Charles R Greathouse IV at Fri Oct 07 02:28:38 EDT 2016

STATUS

editing

approved

#26 by Charles R Greathouse IV at Fri Oct 07 02:28:34 EDT 2016

DATA

1, 511, 713, 11023, 15553, 43873, 81079, 323593, 27923663, 125093857, 466572127, 1108378657, 2214217703, 2871002911, 3501195817, 4107455887, 4609840831, 5066719081, 5488711231, 6331291231, 9396536737

KEYWORD

nonn,more,new

EXTENSIONS

a(11)-a(21) from Charles R Greathouse IV, Oct 07 2016

STATUS

approved

editing

#25 by Vaclav Kotesovec at Thu Oct 06 14:28:39 EDT 2016

STATUS

proposed

approved

#24 by Altug Alkan at Thu Oct 06 11:13:50 EDT 2016

STATUS

editing

proposed

#23 by Charles R Greathouse IV at Tue Oct 04 22:23:48 EDT 2016

PROG

(PARI) list(lim)=my(v=List([1]), t, s, n); lim\=1; forprime(p=3, sqrtint(lim\3), for(e=2, logint(lim, p), t=p^e; forstep(k=3, lim\t, 2, if(k%p==0, next); s=(t*p-1)/(p-1)*sigma(k); n=t*k; if(Mod(2, n)^(s-n)==1, listput(v, n))))); forprime(p=3, lim\3, forstep(k=3, lim\p, 2, if(k%p==0, next); s=(p+1)*sigma(k); n=p*k; if(Mod(2, n)^(s-n)==1, listput(v, n)))); Set(v) \\ Charles R Greathouse IV, Oct 04 2016

STATUS

reviewed

editing

Discussion

Thu Oct 06

11:13

Altug Alkan: May I propose it? Thanks for the Pari script. Best regards.

#22 by Michel Marcus at Tue Oct 04 04:18:14 EDT 2016

STATUS

proposed

reviewed

#21 by Altug Alkan at Mon Oct 03 17:03:35 EDT 2016

STATUS

editing

proposed

#20 by Altug Alkan at Mon Oct 03 16:58:56 EDT 2016

DATA

1, 511, 713, 11023, 15553, 43873, 81079, 323593, 27923663, 125093857

STATUS

proposed

editing