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 A061975 #20 Dec 05 2020 11:16:50
%S A061975 1,3,7,9,21,31,63,751,1743,2205,12345,16689,20111,26607,32247,119595,
%T A061975 437829,2834567
%N A061975 Numbers n such that n divides the (left) concatenation of all numbers <= n written in base 22 (most significant digit on right).
%C A061975 This sequence differs from A029539 in that all least significant zeros are kept during concatenation.
%C A061975 No more terms < 7*10^6. - _Lars Blomberg_, Jul 25 2011
%H A061975 <a href="/index/N#concat">Index entries for related sequences</a>
%e A061975 See A061955 for example.
%t A061975 b = 22; c = {}; Select[Range[10^4], Divisible[FromDigits[c = Join[Reverse[IntegerDigits[#, b]], c], b], #] &] (* _Robert Price_, Mar 09 2020 *)
%o A061975 (PARI) lista(nn, m=22) = my(c, t); for(k=1, nn, t+=m^c*fromdigits(Vecrev(digits(k, m)), m); c+=logint(m*k, m); if(t%k==0, print1(k, ", "))); \\ _Jinyuan Wang_, Dec 05 2020
%Y A061975 Cf. A029447-A029470, A029471-A029494, A029495-A029518, A029519-A029542, A061931-A061954, A061955-A061978.
%K A061975 nonn,base,more
%O A061975 1,2
%A A061975 Larry Reeves (larryr(AT)acm.org), May 24 2001
%E A061975 Edited and updated by Larry Reeves (larryr(AT)acm.org), Apr 12 2002
%E A061975 a(17)-a(18) from _Lars Blomberg_, Jul 25 2011