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 A030521 #19 Oct 06 2019 18:17:37
%S A030521 3,7,31,211,2311,233311,30563611,4615105111,835334024911,
%T A030521 159548798757811,49938774011194531,17628387225951669091,
%U A030521 6575388435279972570571,2518373770712229494528311,1830857731307790842522081371,1385959302599997667789215597091
%N A030521 Product of first n palindromic primes plus 1.
%C A030521 The subsequence of those values which are themselves primes begins: 3, 7, 31, 211, 2311, 6575388435279972570571. - _Jonathan Vos Post_, Feb 09 2011
%t A030521 palpQ[n_]:=Module[{idn=IntegerDigits[n]},idn==Reverse[idn]]; #+1&/@FoldList[ Times, 1,Select[Prime[Range[500]],palpQ]] (* _Harvey P. Dale_, Apr 23 2011 *)
%Y A030521 Cf. A019515, A030522.
%K A030521 nonn,base
%O A030521 1,1
%A A030521 _Felice Russo_
%E A030521 Corrected and extended by _Patrick De Geest_, Sep 15 2000
%E A030521 More terms from _Harvey P. Dale_, Apr 23 2011