login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A029561 Quasi-Carmichael numbers to base 2: squarefree composites n such that prime p|n ==> p-2|n-2. 3

%I #15 Aug 11 2014 22:45:15

%S 1595,6785,53867,67727,102377,296003,740027,961877,998867,1048817,

%T 1270055,1365377,4086227,7715567,12266267,15017921,24960245,33759467,

%U 34918697,36265385,38342397,41048777,44535647,48056087,56264987,58515347

%N Quasi-Carmichael numbers to base 2: squarefree composites n such that prime p|n ==> p-2|n-2.

%C These are called 2-Korselt numbers by Beouallegue et al.

%H Giovanni Resta, <a href="/A029561/b029561.txt">Table of n, a(n) for n = 1..393</a> (terms < 10^12)

%H <a href="/index/Ca#Carmichael">Index entries for sequences related to Carmichael numbers.</a>

%H K. Bouallegue, O. Echi, R. G. E. Pinch, <a href="http://dx.doi.org/10.1142/S1793042110002922 ">Korselt numbers and sets</a>, Int. J. Numb. Theory 6 (2) (2010) 257-269

%t qcm[n_, d_] := Block[{p, e}, {p, e} = Transpose@FactorInteger@n; Length[p] > 1 && Max[e] == 1 && ! MemberQ[p, d] && Max@ Mod[n-d, p-d] == 0]; Select[Range[10^5], qcm[#, 2] &] (* _Giovanni Resta_, May 21 2013 *)

%Y Cf. A120944, A002997.

%K nonn

%O 1,1

%A _David W. Wilson_

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 28 09:04 EDT 2024. Contains 371240 sequences. (Running on oeis4.)