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 A171033 #9 Mar 31 2017 11:12:43
%S A171033 2,3,6,7,11,13,17,19,23,29,31,37,41,43,47,63,69,51,57,71,73,79,83,89,
%T A171033 97,101,103,107,109,113,127,131,137,139,149,161,167,153,157,173,179,
%U A171033 181,191,193,197,199,211,223,227,229,233,239,241,261,267,253
%N A171033 In the sequence of prime numbers, replace all the '6' digits with '5' and vice versa.
%H A171033 Vincenzo Librandi, <a href="/A171033/b171033.txt">Table of n, a(n) for n = 1..1000</a>
%t A171033 FromDigits[IntegerDigits[#]/.{6->p, 5->q}/.{p->5, q->6}]&/@Prime[Range[100]] (* _Vincenzo Librandi_, Apr 07 2013 *)
%o A171033 (PARI) a(n)=my(v=[0,1,2,3,4,6,5,7,8,9]);subst(Pol(apply(k->v[k+1], digits(prime(n)))),'x,10) \\ _Charles R Greathouse IV_, Jul 25 2013
%K A171033 nonn,base,easy
%O A171033 1,1
%A A171033 _N. J. A. Sloane_ and _Vincenzo Librandi_, Sep 04 2010