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 A088554 #12 Jul 05 2024 08:13:07
%S A088554 2,7,31,157,3907,19531,2441407,12207031,61035157,305175781,
%T A088554 9313225746154785157,177635683940025046467781066894531
%N A088554 Primes of the form (5^k-1)/4 or (5^k+3)/4.
%H A088554 Amiram Eldar, <a href="/A088554/b088554.txt">Table of n, a(n) for n = 1..19</a>
%t A088554 With[{kmax = 100}, Select[Flatten[Table[(5^k + {-1, 3})/4, {k, 0, kmax}]], PrimeQ]] (* _Amiram Eldar_, Jul 05 2024 *)
%Y A088554 Cf. A004061.
%K A088554 nonn
%O A088554 1,1
%A A088554 _Cino Hilliard_, Nov 17 2003
%E A088554 Edited by _Don Reble_, May 03 2006