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 A050522 #24 Feb 21 2024 02:19:12
%S A050522 19,79,1279,5119,20479,81919,1310719,21474836479,1407374883553279,
%T A050522 90071992547409919,23611832414348226068479,
%U A050522 1784059615882449851322857461811868920478433279
%N A050522 Primes of form 5*2^n-1.
%H A050522 Heiko Harborth, <a href="http://ami.ektf.hu/uploads/papers/finalpdf/AMI_41_from57to62.pdf">On h-perfect numbers</a>, Annales Mathematicae et Informaticae, 41 (2013) pp. 57-62.
%H A050522 <a href="/index/Pri#riesel">Index entries for sequences of n such that k*2^n-1 (or k*2^n+1) is prime</a>
%F A050522 a(n) = 5*2^A001770(n) - 1. - _Max Alekseyev_, Feb 20 2024
%t A050522 Select[Table[5*2^n-1,{n,0,150}],PrimeQ] (* _Jean-François Alcover_, Mar 21 2011 *)
%Y A050522 See A001770 for more terms.
%K A050522 nonn,nice
%O A050522 1,1
%A A050522 _N. J. A. Sloane_, Dec 29 1999