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 A075013 #5 Apr 11 2020 12:39:49
%S A075013 1,1,1,1,4,1,5,5,4,9,16,1,7,5,4,19,3,13,22,19,16,27,2,19,24,7,31,5,31,
%T A075013 19,27,19,16,3,9,31,26,41,7,19,28,37,20,27,4,51,20,19,16,49,52,35,32,
%U A075013 31,49,5,22,31,66,19,32,27,58,19,9,49,6,35,28,9,26,67,13,63,49,79,16
%N A075013 Smallest k such that the decimal concatenation of k and k+1 is divisible by n.
%e A075013 a(16) = 19 as 16 divides 1920.
%t A075013 With[{cnct=Table[FromDigits[Flatten[IntegerDigits/@{n,n+1}]],{n,100}]},Table[ Position[cnct,_?(Divisible[#,k]&),1,1],{k,100}]]//Flatten (* _Harvey P. Dale_, Apr 11 2020 *)
%o A075013 (PARI) for(n=1,100,k=1:while((k*(10^floor(log(k+1)/log(10)+1))+k+1)%n>0,k=k+1):print1(k","))
%Y A075013 Cf. A075114, A075115, A075116, A075117.
%K A075013 base,nonn
%O A075013 1,5
%A A075013 _Amarnath Murthy_, Sep 01 2002
%E A075013 Corrected and extended by _Ralf Stephan_, Mar 23 2003