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 A222220 #11 Mar 31 2017 00:26:42
%S A222220 0,3,2,1,4,5,6,7,8,9,30,33,32,31,34,35,36,37,38,39,20,23,22,21,24,25,
%T A222220 26,27,28,29,10,13,12,11,14,15,16,17,18,19,40,43,42,41,44,45,46,47,48,
%U A222220 49,50,53,52,51,54,55,56,57,58,59,60,63,62,61,64,65,66,67,68,69,70,73,72,71,74,75
%N A222220 In the number n, replace all (decimal) digits '1' with '3' and vice versa.
%C A222220 The map which is applied to primes in A175770.
%H A222220 Vincenzo Librandi, <a href="/A222220/b222220.txt">Table of n, a(n) for n = 0..1000</a>
%t A222220 a[n_]:= IntegerDigits[n]/.{1->3, 3->1} // FromDigits; Table[a[n], {n, 0, 80}] (* _Vincenzo Librandi_, Jul 29 2013 *)
%o A222220 (PARI) A222220(n,d=[0,3,2,1,4,5,6,7,8,9])=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 A222220 Cf. A222210-A222254; A171013-A171016, A175770, A171018-A171057.
%K A222220 nonn,easy,base
%O A222220 0,2
%A A222220 _M. F. Hasler_, Feb 12 2013