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 A171045 #12 Mar 31 2017 00:52:37
%S A171045 2,3,5,7,11,13,17,19,23,29,31,37,81,83,87,53,59,61,67,71,73,79,43,49,
%T A171045 97,101,103,107,109,113,127,131,137,139,189,151,157,163,167,173,179,
%U A171045 141,191,193,197,199,211,223,227,229,233,239,281,251,257,263
%N A171045 In the sequence of prime numbers, replace all the '8' digits with '4' and vice versa.
%H A171045 Vincenzo Librandi, <a href="/A171045/b171045.txt">Table of n, a(n) for n = 1..1000</a>
%t A171045 FromDigits[IntegerDigits[#] /. {8 -> p, 4 -> q} /. {p -> 4, q -> 8}] & /@ Prime[Range[100]] (* _Harvey P. Dale_, Jun 10 2011 *)
%o A171045 (PARI) a(n)=my(v=[0,1,2,3,8,5,6,7,4,9]);subst(Pol(apply(k->v[k+1], digits(prime(n)))),'x,10) \\ _Charles R Greathouse IV_, Jul 31 2013
%K A171045 nonn,base,easy
%O A171045 1,1
%A A171045 _N. J. A. Sloane_ and _Vincenzo Librandi_, Sep 04 2010