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 A083975 #15 Mar 25 2019 14:02:16
%S A083975 11411,14341,1464641,1447441,1444441,144404441,14244444241,
%T A083975 34444344443,74444444447,1444447444441,3444444444443,144444454444441,
%U A083975 14144444444444141,34444444044444443,1414444444444444141,1444444447444444441,104444444444444444401
%N A083975 Smallest palindromic prime containing exactly n 4's.
%H A083975 Chai Wah Wu, <a href="/A083975/b083975.txt">Table of n, a(n) for n = 1..500</a>
%t A083975 Table[d = 4; i = 1;
%t A083975 While[ x = IntegerDigits[Prime[i]];
%t A083975 x != Reverse[x] || Count[x, d] != n , i++];
%t A083975 FromDigits[x], {n, 1, 6}] (* _Robert Price_, Mar 25 2019 *)
%Y A083975 Cf. A083972, A083973, A083975, A083976, A083977, A083978, A083979, A083980, A083981.
%K A083975 base,nonn
%O A083975 1,1
%A A083975 _Amarnath Murthy_ and Meenakshi Srikanth (menakan_s(AT)yahoo.com), May 21 2003
%E A083975 More terms from _Ray G. Opao_, Sep 20 2004
%E A083975 Corrected and extended by _Giovanni Resta_, Feb 08 2006