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 A115889 #4 Sep 13 2020 19:03:32
%S A115889 1,2,3,6,7,11,99,202,212,222,282,373,404,424,505,525,575,626,636,848,
%T A115889 858,909,1221,2002,2332,2442,2772,3003,3883,4224,4884,6116,6556,6886,
%U A115889 7007,7227,7337,8778,10201,10901,11111,11411,12021,12421,14541,14941
%N A115889 Palindromes equal to the difference between a prime number and its index.
%e A115889 575=p(126)-126.
%t A115889 Select[Union[Flatten[Differences/@Table[{n,Prime[n]},{n,3000}]]], PalindromeQ] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Sep 13 2020 *)
%Y A115889 Cf. A115885.
%K A115889 nonn,base
%O A115889 1,2
%A A115889 _Giovanni Resta_, Feb 06 2006