%I A023203
%S A023203 3,7,13,19,31,37,43,61,73,79,97,103,127,139,157,163,181,223,229,241,271,
%T A023203 283,307,337,349,373,379,409,421,433,439,457,499,547,577,607,631,643,673,
%U A023203 691,709,733,751,787,811,829,853,877,919,937,967,1009,1021,1039,1051
%N A023203 Numbers n such that n and n + 10 are both prime.
%C A023203 A subset of A002476[n] Primes of form 6n + 1. It appears that this is 
               also a subset of the Cuban primes A007645[n] Primes of form x^2+xy+y^2; 
               or: primes of form x^2+3*y^2; or: primes == 0 or 1 mod 3. The first 
               few Cuban primes that are not in this sequence are {67,109,151,193,
               199,211,277,313,331,367,397,463,487,523,541,571,601,613,...}. - Alexander 
               Adamchuk (alex(AT)kolmogorov.com), Aug 15 2006
%C A023203 The entries are all of the cuban form, because they cannot be of the 
               form p=3*k+2. If the were, p+10=3*k+12 were divisible by 3 and not 
               prime. qed. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 
               30 2009]
%H A023203 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               TwinPrimes.html">Link to a section of The World of Mathematics.</
               a>
%t A023203 Do[s=Prime[n]; If[PrimeQ[s+10], Print[Prime[n]]], {n, 1, 1000}]
%Y A023203 Different from A015916. Cf. A031928, A079033.
%Y A023203 Cf. A002476, A007645.
%Y A023203 Sequence in context: A007645 A144919 A015916 this_sequence A086135 A023220 
               A023205
%Y A023203 Adjacent sequences: A023200 A023201 A023202 this_sequence A023204 A023205 
               A023206
%K A023203 nonn
%O A023203 1,1
%A A023203 David W. Wilson (davidwwilson(AT)comcast.net)