%I A071558
%S A071558 4,2,2,1,6,1,6,9,2,3,18,1,24,3,2,12,6,1,12,3,2,9,6,3,6,12,4,15,12,1,42,
%T A071558 6,6,3,12,2,54,6,8,6,30,1,24,15,4,3,6,4,18,3,2,6,120,2,12,48,4,6,18,1,
%U A071558 258,21,14,3,30,3,24,15,2,6,18,1,84,27,2,3,6,4,132,3,10,15,54,5,12,12
%N A071558 Smallest k such that nk+1 and nk-1 are simultaneously primes.
%H A071558 T. D. Noe, <a href="b071558.txt">Table of n, a(n) for n=1..1000</a>
%o A071558 (PARI) for(n=1,100,s=1; while(isprime(s*n+1)*isprime(n*s-1)==0,s++); 
               print1(s,","))
%Y A071558 Cf. A071256
%Y A071558 Sequence in context: A123402 A088570 A102888 this_sequence A136709 A137239 
               A136714
%Y A071558 Adjacent sequences: A071555 A071556 A071557 this_sequence A071559 A071560 
               A071561
%K A071558 easy,nonn
%O A071558 1,1
%A A071558 Benoit Cloitre (benoit7848c(AT)orange.fr), May 30 2002