%I A112879
%S A112879 3,107,206081,20894934252011
%N A112879 Define a(0)=3; then a(n)=k*a(n-1)^2-1=least prime first of twin primes.
%C A112879 k sequence in A112880
%e A112879 12*3^2-1=107, 107 and 109 twin primes so a(1)=107
%e A112879 18*107^2-1=206081, 206081 and 206083 twin primes so a(2)=206081
%e A112879 a(3)=492*(18*(12*3^2-1)^2-1)^2-1
%e A112879 a(4)=702*(492*(18*(12*3^2-1)^2-1)^2-1)^2-1
%e A112879 a(5)=2310*(702*(492*(18*(12*3^2-1)^2-1)^2-1)^2-1)^2-1
%e A112879 a(6)=2370*(2310*(702*(492*(18*(12*3^2-1)^2-1)^2-1)^2-1)^2-1)^2-1
%e A112879 a(7)=130650*(2370*(2310*(702*(492*(18*(12*3^2-1)^2-1)^2-1)^2-1)^2-1)^2-1)^2-1
%e A112879 a(8)=980910*(130650*(2370*(2310*(702*(492*(18*(12*3^2-1)^2-1)^2-1)^2-1)^2-1)^2-1)^2-1)^2-1
%e A112879 a(9)=5528418*(980910*(130650*(2370*(2310*(702*(492*(18*(12*3^2-1)^2-1)^2-1)^2-1)^2-1)^2-1)^2-1)^2-1)^2-1
%e A112879 a(10)=21357012*(5528418*(980910*(130650*(2370*(2310*(702*(492*(18*(12*3^2-1)^2-1)^2-1)^2-1)^2-1)^2-1)^2-1)^2-\
               1)^2-1)^2-1
%Y A112879 Cf. A112880.
%Y A112879 Sequence in context: A003705 A146214 A061308 this_sequence A053861 A041635 
               A142533
%Y A112879 Adjacent sequences: A112876 A112877 A112878 this_sequence A112880 A112881 
               A112882
%K A112879 hard,nonn
%O A112879 0,1
%A A112879 Pierre CAMI (pierrecami(AT)tele2.fr), Oct 01 2005