|
%I #15 Sep 07 2021 15:29:51
%S 17,281,677,953,2729,4241,4637,18749,55217,112997,115769,148781,
%T 151733,326693,623393,637841,744833,907733,1056833,1444481,1774937,
%U 1831481,1866737,1939097,2028197,2564369,2566601,3146237,4635317,4777433,5629157,5960501,6247601,6837221,7248737,7278041,7340537,7442849,7766237
%N Numbers n with property that n==5 (mod 12) and 2^(m-1)=1 (mod m) where m=(2*n-1)*n.
%C All terms <= 10^9 are prime, are there any composite terms?
%t Select[Range[5,777*10^4,12],PowerMod[2,#(2#-1)-1,#(2#-1)]==1&] (* _Harvey P. Dale_, Sep 07 2021 *)
%o (PARI)
%o { forstep (n=5, 10^9, 12,
%o m = (2*n-1)*n;
%o t = Mod(2,m)^(m-1);
%o if ( component(t,2) == 1,
%o print1(n,", "); /* print term */
%o /* if ( !isprime(n), print1(n,", ") ); */ /* print only nonprime terms */
%o ); ); } /* _Joerg Arndt_, Apr 01 2011 */
%K nonn
%O 1,1
%A _Alzhekeyev Ascar M_, Mar 20 2011
|
