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 A056732 #21 May 01 2022 08:39:30
%S A056732 2,11,101,0,10301,0,1003001,0,100030001,0,10000500001,0,1000008000001,
%T A056732 0,100000323000001,0,10000000500000001,0,1000000008000000001,0,
%U A056732 100000000212000000001,0,10000000000300000000001,0,1000000000016100000000001,0
%N A056732 Smallest palindromic prime using n digits, or 0 if no such number exists.
%F A056732 a(2*n) = 0 for n >= 2 (palindromes of even length are divisible by 11). - _Joerg Arndt_, May 01 2022
%t A056732 Do[ k = 10^n; While[ ! PrimeQ[ k*10^n + FromDigits[ Take[ Reverse[ RealDigits[ k ][ [ 1 ] ] ], {2, -1} ] ] ], k++ ]; Print[ k*10^n + FromDigits[ Take[ Reverse[ RealDigits[ k ][ [ 1 ] ] ], {2, -1} ] ] ]; If[ n == 0, Print[ 11 ], Print[ 0 ] ], {n, 0, 12} ]
%Y A056732 Odd-numbered terms form A028989. - _Edward Catmur_, May 01 2015
%K A056732 nonn,base
%O A056732 1,1
%A A056732 _Robert G. Wilson v_, Aug 11 2000
%E A056732 a(25)-a(26) from _Michael S. Branicky_, Feb 12 2021
%E A056732 Name corrected by _Joerg Arndt_, May 01 2022