This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A240839 #16 Nov 29 2014 13:55:49 %S A240839 23,103,293,503,823,883,953,983,1033,1163,1213,1223,1433,1453,1493, %T A240839 1523,1723,1733,1933,1993,2113,2203,2803,2833,2903,3023,3203,3343, %U A240839 3433,3733,3823,3833,4003,4243,4373,4483,4513,4733,4813,4903,4943,4993,5333,5503,5743,6143,6343,6833,7013 %N A240839 Both n and prime(n) are primes congruent to 3 (mod 10). %C A240839 Intersection of A030431 and A049508. %H A240839 Zak Seidov, <a href="/A240839/b240839.txt">Table of n, a(n) for n = 1..469</a> %e A240839 prime(23, 103, 293, 503, 823, 883, 953, 983, 1033, 1163) = (83, 563, 1913, 3593, 6323, 6863, 7523, 7753, 8233, 9403). %t A240839 Intersection[A030431 = Select[Range[3, 1000003, 10], PrimeQ], PrimePi[A030431]] (* gives 469 terms for prime(n) up to 10^6 *) %t A240839 Select[Prime[Range[50000]],Mod[#,10]==Mod[Prime[#],10]==3&] (* gives 3126 terms from the first 50000 primes *)(* _Harvey P. Dale_, Nov 29 2014 *) %o A240839 (PARI) s=[]; forprime(n=2, 8000, if(n%10==3 && prime(n)%10==3, s=concat(s, n))); s \\ _Colin Barker_, Apr 16 2014 %Y A240839 Cf. A030431, A049508. %K A240839 nonn %O A240839 1,1 %A A240839 _Zak Seidov_, Apr 13 2014