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 A048677 #12 Jun 26 2021 17:02:48
%S A048677 2,23,235,2357,235711,235711101,235711101131,235711101131151,
%T A048677 235711101131151181,235711101131151181191,235711101131151181191313,
%U A048677 235711101131151181191313353,235711101131151181191313353373,235711101131151181191313353373383
%N A048677 Concatenation of first n palindromic primes.
%t A048677 With[{pr=Select[Prime[Range[150]],IntegerDigits[#]==Reverse[ IntegerDigits[ #]]&]}, Table[ FromDigits[ Flatten[IntegerDigits/@Take[pr,n]]],{n,Length[ pr]}]] (* _Harvey P. Dale_, Mar 05 2014 *)
%Y A048677 Cf. A002385.
%K A048677 base,nonn
%O A048677 1,1
%A A048677 _Felice Russo_, corrected Sep 13 2000
%E A048677 More terms from _Harvey P. Dale_, Mar 05 2014