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 A099744 #10 Mar 26 2021 18:01:29
%S A099744 3,5,6,222,282,353,434,555,626,656,747,828,858,929,939,10301,10601,
%T A099744 11411,11711,12821,12921,13431,13731,14141,14241,14741,15951,16161,
%U A099744 17171,17771,18381,18981,19191,19491,19991,20402,20702,22022,22322
%N A099744 Palindromes n such that 10n01 is a prime.
%H A099744 Harvey P. Dale, <a href="/A099744/b099744.txt">Table of n, a(n) for n = 1..1000</a>
%p A099744 read transforms; pal:=[]; for n from 0 to 8000 do if digrev(n) = n then pal:=[op(pal),n]; fi; od:
%p A099744 t0:=[]; u0:=[]; for n from 1 to nops(pal) do m:=pal[n]; p0:="10"; p1:="01"; t1:=cat(p0,m,p1); t1:=convert(t1,decimal,10); if isprime(t1) then t0:=[op(t0),m]; u0:=[op(u0),t1]; fi; od: t0; # u0 gives A099746.
%t A099744 p = Select[ Range[ 22322], # == FromDigits[ Reverse[ IntegerDigits[ # ]]] &]; Select[p, PrimeQ[ FromDigits[ Join[{1, 0}, IntegerDigits[ # ], {0, 1}]]] &] (* _Robert G. Wilson v_, Nov 20 2004 *)
%t A099744 Select[Range[23000],PalindromeQ[#]&&PrimeQ[FromDigits[Join[{1,0},IntegerDigits[ #],{0,1}]]]&] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Mar 26 2021 *)
%Y A099744 Cf. A002113, A099746, A032672, A099720, A100026, A100027.
%K A099744 nonn,easy,base
%O A099744 1,1
%A A099744 _N. J. A. Sloane_, Nov 19 2004
%E A099744 More terms from _Robert G. Wilson v_, Nov 19 2004