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 A171052 #13 Mar 31 2017 00:46:17
%S A171052 2,9,5,7,11,19,17,13,29,23,91,97,41,49,47,59,53,61,67,71,79,73,89,83,
%T A171052 37,101,109,107,103,119,127,191,197,193,143,151,157,169,167,179,173,
%U A171052 181,131,139,137,133,211,229,227,223,299,293,241,251,257,269
%N A171052 In the sequence of prime numbers, replace all the '9' digits with '3' and vice versa.
%H A171052 Vincenzo Librandi, <a href="/A171052/b171052.txt">Table of n, a(n) for n = 1..1000</a>
%t A171052 FromDigits[IntegerDigits[#] /. {3 -> x, 9 -> y} /. {x -> 9, y -> 3}] & /@ Prime[Range[60]] (* _Harvey P. Dale_, Feb 23 2011 *)
%o A171052 (PARI) a(n)=my(v=[0,1,2,9,4,5,6,7,8,3]);subst(Pol(apply(k->v[k+1], digits(prime(n)))),'x,10) \\ _Charles R Greathouse IV_, Jul 31 2013
%K A171052 nonn,base,easy
%O A171052 1,1
%A A171052 _N. J. A. Sloane_ and _Vincenzo Librandi_, Sep 04 2010