%I #18 Mar 08 2020 23:54:32

%S 1,12,270,402,9396,17490,187932,488214,2936526,7900764

%N a(1) is the least k such that j(1) = k*2*3 - 1 is the lesser of a twin prime pair; then for n > 1, a(n) is the least k greater than a(n-1) such that j(n) = k*j(n-1)*(j(n-1)+2) - 1 is the lesser of a twin prime pair.

%H Pierre CAMI, <a href="/A107485/a107485.txt">PFGW Script</a>

%e 1*2*3 - 1 = 5, 5 and 7 twin primes, a(1) = 1.

%e 12*5*7 - 1 = 419, 419 and 421 twin primes, a(2) = 12.

%e 270*419*421 - 1 = 47627729, 47627729 and 4762731 twin primes, a(3) = 270.

%o (PARI) lista(nn) = {my(j=5, k=1, m); print1(k); for(n=2, nn, m=j*(j+2); j=k*m-1; while(ispseudoprime(j+=m)+ispseudoprime(j+2)<2, k++); print1(", ", k++)); } \\ _Jinyuan Wang_, Mar 05 2020

%K nonn,more

%O 1,2

%A _Pierre CAMI_, May 28 2005

%E a(8) corrected by _Jinyuan Wang_, Mar 05 2020

%E Name clarified by _Michel Marcus_, Mar 07 2020

%E a(9)-a(10), computed by _Pierre CAMI_, added by _Michel Marcus_, Mar 08 2020