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 A171040 #10 Mar 31 2017 11:06:28
%S A171040 2,3,5,6,11,13,16,19,23,29,31,36,41,43,46,53,59,71,76,61,63,69,83,89,
%T A171040 96,101,103,106,109,113,126,131,136,139,149,151,156,173,176,163,169,
%U A171040 181,191,193,196,199,211,223,226,229,233,239,241,251,256,273
%N A171040 In the sequence of prime numbers, replace all the '7' digits with '6' and vice versa.
%H A171040 Vincenzo Librandi, <a href="/A171040/b171040.txt">Table of n, a(n) for n = 1..1000</a>
%t A171040 FromDigits[IntegerDigits[#]/.{7->p, 6->q}/.{p->6, q->7}]&/@Prime[Range[100]] (* _Vincenzo Librandi_, Mar 11 2013 *)
%o A171040 (PARI) a(n)=my(v=[0,1,2,3,4,5,7,6,8,9]);subst(Pol(apply(k->v[k+1], digits(prime(n)))),'x,10) \\ _Charles R Greathouse IV_, Jul 26 2013
%K A171040 nonn,base,easy
%O A171040 1,1
%A A171040 _N. J. A. Sloane_ and _Vincenzo Librandi_, Sep 04 2010