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 A222252 #11 Mar 30 2017 22:38:47
%S A222252 0,1,2,3,4,5,6,8,7,9,10,11,12,13,14,15,16,18,17,19,20,21,22,23,24,25,
%T A222252 26,28,27,29,30,31,32,33,34,35,36,38,37,39,40,41,42,43,44,45,46,48,47,
%U A222252 49,50,51,52,53,54,55,56,58,57,59,60,61,62,63,64,65,66,68,67,69,80,81,82,83,84,85
%N A222252 In the number n, replace all (decimal) digits '7' with '8' and vice versa.
%C A222252 The map which is applied to primes in A171048.
%H A222252 Vincenzo Librandi, <a href="/A222252/b222252.txt">Table of n, a(n) for n = 0..1000</a>
%t A222252 a[n_]:= IntegerDigits[n]/.{7->8,8->7} // FromDigits; Table[a[n], {n, 0, 80}] (* _Vincenzo Librandi_, Jul 29 2013 *)
%o A222252 (PARI) A222252(n,d=[0, 1, 2, 3, 4, 5, 6, 8, 7, 9])=sum(i=1, #n=digits(n), d[n[i]+1]*10^(#n-i)) \\ gives correct value for n=0 iff d[1]=0, since digits(0)=[] in PARI (v.2.6)
%Y A222252 Cf. A222210-A222254; A171013-A171016, A175770, A171018-A171057.
%K A222252 nonn,base,easy
%O A222252 0,3
%A A222252 _M. F. Hasler_, Feb 13 2013
%E A222252 Corrected term by _Vincenzo Librandi_, Jul 29 2013