A158195 - OEIS

%I #15 Sep 30 2016 16:49:44

%S 13,19,31,37,59,73,103,109,127,149,163,167,181,211,239,257,271,293,

%T 307,347,383,419,433,491,499,509,523,541,563,613,617,631,653,743,761,

%U 769,787,811,859,877,941,967,1009,1021,1049,1063,1117,1153,1171,1193,1201

%N Prime numbers such that sum of digits is even semiprime.

%C Even semiprime = 2*prime.

%H Harvey P. Dale, <a href="/A158195/b158195.txt">Table of n, a(n) for n = 1..1000</a>

%e 13(1+3=2*2), 19(1+9=2*5), 31(3+1=2*2), 37(3+7=2*5), 59(5+9=2*7).

%t Select[Prime[Range[200]],PrimeQ[Total[IntegerDigits[#]]/2]&] (* _Peter J. C. Moses_, Jun 05 2014 *)

%t Select[Prime[Range[200]],EvenQ[Total[IntegerDigits[#]]]&& PrimeOmega[ Total[ IntegerDigits[ #]]] ==2&] (* _Harvey P. Dale_, Sep 30 2016 *)

%o (PARI) isok(n) = isprime(n) && (q = sumdigits(n)/2) && (type(q) == "t_INT") && isprime(q); \\ _Michel Marcus_, Jun 24 2014

%Y Cf. A000040, A100484.

%K nonn,base,easy,less

%O 1,1

%A _Juri-Stepan Gerasimov_, Mar 13 2009

%E 257 added by _R. J. Mathar_, Mar 15 2009