login
Pseudoprimes to base 14.
2

%I #21 Jun 13 2018 03:35:38

%S 15,39,65,195,481,561,781,793,841,985,1105,1111,1541,1891,2257,2465,

%T 2561,2665,2743,3277,5185,5713,6501,6533,6541,7107,7171,7449,7543,

%U 7585,8321,9073,10585,12403,12505,12545,12805,12871,13429,14111,14689,15067,15457

%N Pseudoprimes to base 14.

%C Composite numbers n such that 14^(n-1) == 1 (mod n). - _Michel Lagneau_, Feb 18 2012

%H T. D. Noe, <a href="/A020142/b020142.txt">Table of n, a(n) for n = 1..1000</a>

%H <a href="/index/Ps#pseudoprimes">Index entries for sequences related to pseudoprimes</a>

%p select(t -> not isprime(t) and 14 &^ (t-1) mod t = 1, [seq(i,i=3..20000,2)]); # _Robert Israel_, Jun 12 2018

%t pseudos14 = {}; n = 1; While[Length[pseudos14] < 100, n++; If[!PrimeQ[n] && PowerMod[14, n - 1, n] == 1, AppendTo[pseudos14, n]]]; pseudos14 (* _T. D. Noe_, Feb 21 2012 *)

%Y Cf. A001567 (pseudoprimes to base 2).

%K nonn

%O 1,1

%A _David W. Wilson_