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 A171054 #11 Mar 31 2017 00:45:28
%S A171054 2,3,9,7,11,13,17,15,23,25,31,37,41,43,47,93,95,61,67,71,73,75,83,85,
%T A171054 57,101,103,107,105,113,127,131,137,135,145,191,197,163,167,173,175,
%U A171054 181,151,153,157,155,211,223,227,225,233,235,241,291,297,263
%N A171054 In the sequence of prime numbers, replace all the '9' digits with '5' and vice versa.
%H A171054 Vincenzo Librandi, <a href="/A171054/b171054.txt">Table of n, a(n) for n = 1..1000</a>
%t A171054 FromDigits[IntegerDigits[#] /. {9 -> p, 5 -> q} /. {p -> 5, q -> 9}] & /@ Prime[Range[100]] (* _Vincenzo Librandi_, Apr 07 2013 *)
%o A171054 (PARI) a(n)=my(v=[0,1,2,3,4,9,6,7,8,5]);subst(Pol(apply(k->v[k+1], digits(prime(n)))),'x,10) \\ _Charles R Greathouse IV_, Jul 31 2013
%K A171054 nonn,base,easy
%O A171054 1,1
%A A171054 _N. J. A. Sloane_ and _Vincenzo Librandi_, Sep 04 2010