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 A279798 #26 Jun 11 2022 05:22:50
%S A279798 67,104743,8609,281,521,1163,1436471,12391,136343,1483,23663,727,
%T A279798 10453,2029,135481883,7429021,2059324621,6864415403,3716857,9629,
%U A279798 451358821,51782483,62504399,439322585771,63337,128110399,42209,59569669,111486983,10936129,31585821557
%N A279798 Largest prime factor of 78557*2^n + 1.
%C A279798 a(n) <= A258073(n) / A258091(n).
%H A279798 Daniel Suteu, <a href="/A279798/b279798.txt">Table of n, a(n) for n = 1..412</a>
%H A279798 Wikipedia, <a href="http://en.wikipedia.org/wiki/Sierpinski_number">Sierpinski Number</a>
%F A279798 a(n) = A006530(A258073(n)).
%e A279798 78557 * 2^1 + 1 = 157115 = 5 * 7 * 67^2. So a(1) = 67.
%e A279798 78557 * 2^2 + 1 = 314229 = 3 * 104743. So a(2) = 104743.
%t A279798 Table[FactorInteger[2^n * 78557 + 1][[-1, 1]], {n, 30}] (* _Alonso del Arte_, Jan 01 2017 *)
%o A279798 (PARI) a(n) = my(k=78557*2^n+1); factor(k)[omega(k), 1] \\ _Felix Fröhlich_, Jan 01 2017
%Y A279798 Cf. A002587, A258073, A258091.
%K A279798 nonn
%O A279798 1,1
%A A279798 _Seiichi Manyama_, Dec 19 2016