%I A143394
%S A143394 0,3,0,2,3,2,3,2,109,1291,3,557,211,3,3,7,7,3,2,13,2,5,43,97,2,3,149,43,
%T A143394 5,3,5,13,3,2,7,3,5,197,13,73,7,11,229,23,3,5,3,23,13,2,19,7,5,109,283,
%U A143394 67,7,3,11,13,2,43,2,19,233,7,1061,3,3,149,43,421,11,113,29,7,991,41,61
%N A143394 Least prime a(n) such that a(n)*(a(n)+p(n))-1 and a(n)*(a(n)+p(n))+1 
               are twin primes or 0 if not such prime exist, with p(i)=i-th prime.
%C A143394 no first of twin primes of the form a*(a+2)-1 for a prime
%C A143394 only one first of twin primes of the form a*(a+3)-1 for a=3
%C A143394 no first of twin primes of the form a*(a+5)-1 for a prime
%H A143394 Pierre CAMI, <a href="b143394.txt">Table of n, a(n) for n = 1..12250</
               a>
%e A143394 3*(3+3)-1=17 prime so a(2)=3 as p(2)=3 and 17 and 19 twin primes
%Y A143394 Cf. A143393.
%Y A143394 Sequence in context: A013307 A119493 A032531 this_sequence A112455 A001608 
               A159977
%Y A143394 Adjacent sequences: A143391 A143392 A143393 this_sequence A143395 A143396 
               A143397
%K A143394 nonn
%O A143394 1,2
%A A143394 Pierre CAMI (pierrecami(AT)tele2.fr), Aug 12 2008