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 A222253 #10 Mar 30 2017 22:38:19
%S A222253 0,1,2,3,4,5,6,9,8,7,10,11,12,13,14,15,16,19,18,17,20,21,22,23,24,25,
%T A222253 26,29,28,27,30,31,32,33,34,35,36,39,38,37,40,41,42,43,44,45,46,49,48,
%U A222253 47,50,51,52,53,54,55,56,59,58,57,60,61,62,63,64,65,66,69,68,67,90,91,92,93,94,95
%N A222253 In the number n, replace all (decimal) digits '7' with '9' and vice versa.
%C A222253 The map which is applied to primes in A171056.
%H A222253 Vincenzo Librandi, <a href="/A222253/b222253.txt">Table of n, a(n) for n = 0..1000</a>
%t A222253 a[n_]:= IntegerDigits[n]/.{7->9, 9->7}//FromDigits; Table[a[n], {n, 0, 80}] (* _Vincenzo Librandi_, Jul 29 2013 *)
%o A222253 (PARI) A222253(n,d=[0, 1, 2, 3, 4, 5, 6, 9, 8, 7])=sum(i=1,#n=digits(n),d[n[i]+1]*10^(#n-i),!n*d[1]) \\ N.B.: digits(0)=[] in PARI (v.2.6)
%Y A222253 Cf. A222210-A222254; A171013-A171016, A175770, A171018-A171057.
%K A222253 nonn,base,easy
%O A222253 0,3
%A A222253 _M. F. Hasler_, Feb 13 2013