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 A254673 #7 Sep 08 2022 08:46:11 %S A254673 3,5,7,11,13,23,47,59,71,73,79,97,103,113,127,137,181,199,251,263,271, %T A254673 281,293,331,359,367,397,419,433,443,449,457,463,487,503,523,541,571, %U A254673 607,613,617,631,653,709,719,751,761,773,829,839,877,881,953,967,971 %N A254673 Primes prime(n) such that prime(n) + 4*n is also prime. %H A254673 Vincenzo Librandi, <a href="/A254673/b254673.txt">Table of n, a(n) for n = 1..1000</a> %e A254673 prime(4)=7 is in the sequence because 7+4*4 = 23 is prime. %e A254673 prime(6)=13 is in the sequence because 13+4*6 = 37 is prime. %t A254673 Prime[Select[Range[180], PrimeQ[Prime[#] + 4 #] &]] %o A254673 (Magma) [NthPrime(n): n in [1..200] | IsPrime(NthPrime(n)+4*n)] %Y A254673 Cf. A061067, A231232, A231383, A254462, A254665, A254672. %K A254673 nonn %O A254673 1,1 %A A254673 _Vincenzo Librandi_, Feb 05 2015