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 A082584 #20 May 19 2024 13:14:50
%S A082584 313,353,373,383,727,757,787,797,11311,11411,1311131,1317131,1513151,
%T A082584 1917191,9196919,9199919,10301110301,10301910301,10501210501,
%U A082584 10501910501,10601110601,12421212421,12421812421,12721612721,13331113331,13331713331,13831913831,13931413931
%N A082584 Fractal palindromic primes of first order.
%C A082584 A first order fractal palindromic prime is one of the form WmW, where either wing W about a central digit m, is itself a palindromic prime, which, however, may not be further split in this manner to maintain the property.
%C A082584 [Log_10(a(n))] must be of the form k2. - _Robert G. Wilson v_, Jul 22 2005
%H A082584 Michael S. Branicky, <a href="/A082584/b082584.txt">Table of n, a(n) for n = 1..21046</a> (all terms < 10^26, corresponding to b-file of A082598)
%e A082584 12421812421 is in the sequence because it is a concatenation of the palindromic prime part 12421 with itself, hinging over the central 8;12421 cannot however be split into simpler palindromic primes in this way.
%t A082584 f[n_] := Block[{m = n}, pd = IntegerDigits[m]; pd = Take[pd, Floor[Length[pd]/2]]; If[PrimeQ[m] && PrimeQ[FromDigits[pd]] && pd == Reverse[pd] && m == FromDigits[Reverse[IntegerDigits[m]]] && ! f[FromDigits[pd]], True, False]]; Do[ If[ f[n], Print[n]], {n, 10^10}] (* _Robert G. Wilson v_, Jul 22 2005 *)
%Y A082584 Cf. A002385.
%K A082584 base,nonn
%O A082584 1,1
%A A082584 _Lekraj Beedassy_, May 07 2003
%E A082584 a(25) and beyond from _Michael S. Branicky_, May 19 2024