%I #3 Jul 14 2012 11:32:33

%S 37,1123,1327,2347,3163,59119,71143,79159,101203,113227,151303,163327,

%T 173347,193387,199399,229459,269539,281563,331663,359719,383767,

%U 431863,491983,5091019,5691139,6611323,7091419,7191439,8291659,8391679,8531707

%N Primes which are the concatenation of a prime p and 2p+1.

%C The corresponding primes p are listed in A168164.

%C Contains the subsequence A168165 (where p is restricted to be a Sophie Germain prime).

%o (PARI) forprime(p=1,999, isprime(eval(Str(p,2*p+1))) & print1(p,2*p+1,", "))

%K base,nonn

%O 1,1

%A _M. F. Hasler_, Nov 25 2009