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!)
A029558 Quasi-Carmichael numbers to base 5: squarefree composites n such that (n,2*3) = 1 and prime p|n ==> p-5|n-5. 2

%I #15 May 21 2013 11:15:30

%S 77,221,2093,3311,8897,10373,33143,35717,48581,52421,54677,61997,

%T 65021,73337,108383,112217,119621,134357,143429,155237,200777,214709,

%U 238901,252197,261749,283871,302789,358853,363263,378437,388841,407813,420893

%N Quasi-Carmichael numbers to base 5: squarefree composites n such that (n,2*3) = 1 and prime p|n ==> p-5|n-5.

%C If multiples of 2 and 3 are not excluded, then terms like 21, 1677, 3477, 75621,... belong to the sequence. - _Giovanni Resta_, May 21 2013

%H Giovanni Resta, <a href="/A029558/b029558.txt">Table of n, a(n) for n = 1..6707</a> (terms < 10^12)

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

%t qcm[n_, d_] := Block[{p, e}, {p, e} = Transpose@FactorInteger@n; Length[p] > 1 && Max[e] == 1 && d < Min[p] && And @@ IntegerQ /@ ((n - d)/(p - d))]; Select[Range[10^6], qcm[#, 5] &] (* _Giovanni Resta_, May 21 2013 *)

%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 April 19 17:39 EDT 2024. Contains 371797 sequences. (Running on oeis4.)