%I A128030
%S A128030 2,3,31,467,1747
%N A128030 Numbers n such that (16^n - 3^n)/13 is prime.
%C A128030 All terms are primes.
%t A128030 k=13; Select[ Prime[ Range[1,200] ], PrimeQ[ ((k+3)^# - 3^#)/k ]& ]
%Y A128030 Cf. A028491 = numbers n such that (3^n - 1)/2 is prime. Cf. A057468 = 
               numbers n such that 3^n - 2^n is prime. Cf. A059801 = numbers n such 
               that 4^n - 3^n is prime. Cf. A121877 = numbers n such that (5^n - 
               3^n)/2 is a prime. Cf. A128024, A128025, A128026, A128027, A128028, 
               A128029, A128031, A128032.
%Y A128030 Sequence in context: A029973 A054551 A049065 this_sequence A004843 A032815 
               A041053
%Y A128030 Adjacent sequences: A128027 A128028 A128029 this_sequence A128031 A128032 
               A128033
%K A128030 hard,more,nonn
%O A128030 1,1
%A A128030 Alexander Adamchuk (alex(AT)kolmogorov.com), Feb 11 2007
%E A128030 1747 from Farideh Firoozbakht (mymontain(AT)yahoo.com), Apr 08 2007