%I A071576
%S A071576 1,1,1,165,5415,12705,256410,256410,6480303060,217245863835,
%T A071576 946622690475,35511547806735,439116128090640
%N A071576 a(n) = least k such that 2ik+1 is prime for all 1<=i<=n.
%t A071576 k = 1; Do[ While[p = Table[2*i*k + 1, {i, 1, n}]; Union[ PrimeQ[p]] != 
               {True}, k++ ]; Print[k], {n, 1, 15}] (Robert G. Wilson v)
%o A071576 (PARI) for(n=1,6,s=1; while(sum(i=1,n,isprime(2*s*i+1))<n,s++); print1(s,
               ","))
%Y A071576 Cf. A088250, A124516, A124522, A124522, A063983.
%Y A071576 Cf. A005097, A123998, A124408-A124411.
%Y A071576 Sequence in context: A027796 A145055 A105944 this_sequence A140912 A132055 
               A046178
%Y A071576 Adjacent sequences: A071573 A071574 A071575 this_sequence A071577 A071578 
               A071579
%K A071576 more,nonn
%O A071576 1,4
%A A071576 Benoit Cloitre (benoit7848c(AT)orange.fr), May 31 2002
%E A071576 Extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Jun 06 2002
%E A071576 a(9) from Ryan Propper (rpropper(AT)stanford.edu), Jun 20 2005
%E A071576 a(10)-a(13) from Don Reble (djr(AT)nk.ca), Nov 05 2006