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 A247874 #13 Sep 25 2014 21:47:12
%S A247874 29,137,197,281,419,617,641,809,1061,1091,1229,1289,1427,1481,1877,
%T A247874 1931,2129,2237,2267,2381,2549,2657,2687,2801,2969,3329,3359,3389,
%U A247874 3527,3557,3581,3917,4001,4229,4337,4421,4481,4649,4787,5009,5657,5741,5849,5879,6131,6269,6299,6551,6689,7307
%N A247874 Lesser of twin primes (p, q=p+2) such that 7 is a square mod p and mod q.
%C A247874 Both p and p + 2 are terms in A038878.
%C A247874 All terms are congruent to {1, 25, 27} mod 28.
%H A247874 Zak Seidov, <a href="/A247874/b247874.txt">Table of n, a(n) for n = 1..1000</a>
%e A247874 7+29*1=36=6^2 and 7+31*3=100=10^2 hence 7 is a square mod 29 and mod 31.
%t A247874 Select[Prime[Range[5,1000]], PrimeQ[# + 2] && JacobiSymbol[7, #] == JacobiSymbol[7, # + 2] == 1 &]
%o A247874 (PARI) lista(nn) = {forprime(p=2, nn, if (isprime(q=p+2) && issquare(Mod(7, p)) && issquare(Mod(7, q)), print1(p, ", ")););} \\ _Michel Marcus_, Sep 25 2014
%Y A247874 Cf. A001359, A038878.
%K A247874 nonn
%O A247874 1,1
%A A247874 _Zak Seidov_, Sep 25 2014