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 A099552 #7 Nov 30 2022 19:13:09
%S A099552 1,2,3,2,5,2,5,6,1,10,2,12,5,14,5,6,8,10,15,20,7,6,18,24,25,6,32,32,3,
%T A099552 10,1,12,41,34,5,6,8,46,33,20,34,36,21,24,30,36,36,48,23,50,56,44,34,
%U A099552 42,30,48,9,26,4,60,44,34,33,60,65,28,16,32,66,20,29,44,78,48,75,52,9,8,37
%N A099552 a(n) is the smallest positive integer such that the concatenation of the first n terms is divisible by n.
%H A099552 Paul Tek, <a href="/A099552/b099552.txt">Table of n, a(n) for n = 1..10000</a>
%t A099552 spi[{ctn_,n_,a_}]:=Module[{k=1},While[Mod[ctn*10^IntegerLength[k]+k,n+1] != 0,k++];{ctn*10^IntegerLength[k]+k,n+1,k}]; NestList[spi,{1,1,1},80][[All,3]] (* _Harvey P. Dale_, Nov 30 2022 *)
%o A099552 (PARI) num = 1; print(1); for (n = 2, 9, c = 10*num%n; d = n - c; print(d); num = 10*num + d); for (n = 10, 90, c = 10*num%n; d = n - c; if (d < 10, print(d); num = 10*num + d, c = 100*num%n; d = n - c; if (d < 10, d = d + n); print(d); num = 100*num + d));
%Y A099552 Cf. A051883, A073893, A083161, A100769.
%K A099552 base,easy,nonn
%O A099552 1,2
%A A099552 _David Wasserman_, Oct 21 2004