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 A359436 #28 Sep 10 2024 11:53:06
%S A359436 3,5,7,13,29,61,383,401,1637,1871,36229,44771,44797,75167
%N A359436 Primes p such that (4^p - 2^p + 1)/3 is prime.
%C A359436 Terms > 1871 correspond to probable primes.
%C A359436 Is 9 the only composite k such that (4^k - 2^k + 1)/3 is prime? Checked up to 20000. - _Andrew Howroyd_, Sep 10 2024
%e A359436 3 is a term because 3 is prime and (4^3 - 2^3 + 1)/3 = 19 is also prime.
%o A359436 (PARI) isok(k)={k%2 && ispseudoprime((4^k - 2^k + 1)/3)}
%o A359436 { forprime(p=3, 2000, if(isok(p), print1(p, ", "))) } \\ _Andrew Howroyd_, Dec 31 2022
%Y A359436 Cf. A000978.
%K A359436 nonn,more,hard
%O A359436 1,1
%A A359436 _Jorge Coveiro_, Dec 31 2022