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 A171015 #10 Mar 31 2017 20:32:20
%S A171015 1,3,5,7,22,23,27,29,13,19,32,37,42,43,47,53,59,62,67,72,73,79,83,89,
%T A171015 97,202,203,207,209,223,217,232,237,239,249,252,257,263,267,273,279,
%U A171015 282,292,293,297,299,122,113,117,119,133,139,142,152,157,163
%N A171015 In the sequence of prime numbers, replace all the '2' digits with '1' and vice versa.
%H A171015 Vincenzo Librandi, <a href="/A171015/b171015.txt">Table of n, a(n) for n = 1..1000</a>
%t A171015 FromDigits[IntegerDigits[#]/.{2->p, 1->q}/.{p->1, q->2}]&/@Prime[Range[100]] (* _Vincenzo Librandi_, Mar 12 2013 *)
%o A171015 (PARI) a(n)=my(v=[0,2,1,3,4,5,6,7,8,9]);subst(Pol(apply(k->v[k+1], digits(prime(n)))),'x,10) \\ _Charles R Greathouse IV_, Jul 16 2013
%K A171015 nonn,base,easy
%O A171015 1,2
%A A171015 _N. J. A. Sloane_ and _Vincenzo Librandi_, Sep 04 2010