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 A061942 #28 Feb 03 2025 13:44:37
%S A061942 1,3,9,16,27,33,48,81,144,320,880,1041,2304,2645,8189,15368,29040,
%T A061942 77864,80192,95568,551520,783408,1973640,2162592,2352811,2433557,
%U A061942 7598977
%N A061942 Numbers n such that n divides the (right) concatenation of all numbers <= n written in base 13 (most significant digit on right, least significant zeros not written).
%C A061942 This sequence differs from A029506 in that all least significant zeros are removed before concatenation.
%C A061942 No more terms < 10^7. - _Lars Blomberg_, Oct 20 2011
%H A061942 <a href="/index/N#concat">Index entries for related sequences</a>
%e A061942 See A061931 for example.
%t A061942 b = 13; c = {}; Select[Range[10^4], Divisible[FromDigits[c = Join[c, IntegerDigits[IntegerReverse[#, b], b]], b], #] &] (* _Robert Price_, Mar 08 2020 *)
%o A061942 (PARI) lista(nn, m=13) = my(s, t); for(k=1, nn, s=k/m^valuation(k, m); while(s, t=t*m+s%m; s\=m); if(t%k==0, print1(k, ", "))); \\ _Jinyuan Wang_, Dec 05 2020
%Y A061942 Cf. A029447-A029470, A029471-A029494, A029495-A029518, A029519-A029542, A061931-A061954, A061955-A061978.
%K A061942 nonn,base,more
%O A061942 1,2
%A A061942 Larry Reeves (larryr(AT)acm.org), May 24 2001
%E A061942 Edited and updated by Larry Reeves (larryr(AT)acm.org), Apr 12 2002; Aug 25 2002
%E A061942 a(22)-a(27) from _Lars Blomberg_, Oct 20 2011