%I A117708
%S A117708 3,7,13,31,37,67,127,211,307,409,487,541,577,631,769,787,937,991,1009,
%T A117708 1039,1117,1201,1291,1459,1471,1567,1777,1801,2251,2281,2467,2557,2647,
%U A117708 2971,3037,3187,3259,3307,3559,3709,3847,3889,4441,4567,4801,4969,4987
%N A117708 Numbers that are both lucky numbers and Chen primes.
%t A117708 lst = Range[1, 5000, 2]; i = 2; While[ i <= (len = Length@lst) && (k 
               = lst[[i]]) <= len, lst = Drop[lst, {k, len, k}]; i++ ]; chenQ[n_] 
               := PrimeQ[n] && Plus @@ Last /@ FactorInteger[n + 2] < 3; Select[lst, 
               chenQ@# &] - Robert G. Wilson v (rgwv(at)rgwv.com), May 12 2006
%Y A117708 Cf. A031157, A109611.
%Y A117708 Cf. A031157, A109611.
%Y A117708 Sequence in context: A136051 A100750 A105435 this_sequence A093431 A083520 
               A162869
%Y A117708 Adjacent sequences: A117705 A117706 A117707 this_sequence A117709 A117710 
               A117711
%K A117708 nonn
%O A117708 1,1
%A A117708 Jani Melik (jani_melik(AT)hotmail.com), Apr 27 2006
%E A117708 Corrected and extended by Robert G. Wilson v (rgwv(at)rgwv.com), May 
               12 2006