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 A262497 #11 Oct 02 2015 13:06:52
%S A262497 11111,121111121,71211111217,3712111112173,98371211111217389,
%T A262497 129837121111121738921,3312983712111112173892133,
%U A262497 1063312983712111112173892133601,12106331298371211111217389213360121,781210633129837121111121738921336012187
%N A262497 Minimal nested palindromic primes with seed 11111.
%C A262497 Let s be a palindrome and put a(1) = s. Let a(2) be the least palindromic prime having s in the middle; for n > 2, let a(n) be the least palindromic prime having a(n-1) in the middle. Then (a(n)) is the sequence of minimal nested palindromic primes with seed s.
%H A262497 Clark Kimberling, <a href="/A262497/b262497.txt">Table of n, a(n) for n = 1..200</a>
%e A262497 As a triangle:
%e A262497 11111
%e A262497 121111121
%e A262497 71211111217
%e A262497 3712111112173
%e A262497 98371211111217389
%e A262497 129837121111121738921
%e A262497 3312983712111112173892133
%e A262497 1063312983712111112173892133601
%t A262497 s0 = "11111"; s = {ToExpression[s0]};Do[NestWhile[# + 1 &, 1, ! PrimeQ[tmp = FromDigits[Join[#, IntegerDigits[Last[s], 10, Max[StringLength[s0],Length[IntegerDigits[Last[s]]]]], Reverse[#]]&[IntegerDigits[#]]]] &]; AppendTo[s, tmp], {10}]; s0 <> ", " <> StringTake[ToString[Rest[s]], {2, -2}]
%t A262497 (* _Peter J. C. Moses_, Sep 23 2015 *)
%Y A262497 Cf. A261881.
%K A262497 nonn,base,easy
%O A262497 1,1
%A A262497 _Clark Kimberling_, Sep 24 2015