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 A029514 #21 Jan 14 2025 11:18:20
%S A029514 1,3,5,7,15,25,55,80,143,187,192,387,1385,1760,4080,9040,9245,15565,
%T A029514 17776,20080,28400,30019,30063,37312,38368,52217,56277,84480,97504,
%U A029514 123040,293045,458560,1258528,2437600,2442000,3122240,7216880
%N A029514 Numbers n such that n divides the (right) concatenation of all numbers <= n written in base 21 (most significant digit on right).
%C A029514 This sequence differs from A061950 in that all least significant zeros are kept during concatenation.
%C A029514 No more terms < 10^7. [_Lars Blomberg_, Oct 11 2011]
%H A029514 <a href="/index/N#concat">Index entries for related sequences</a>
%e A029514 See A029495 for example.
%t A029514 b = 21; c = {}; Select[Range[10^4], Divisible[FromDigits[c = Join[c, Reverse[IntegerDigits[#, b]]], b], #] &] (* _Robert Price_, Mar 13 2020 *)
%Y A029514 Cf. A029447-A029470, A029471-A029494, A029495-A029518, A029519-A029542, A061931-A061954, A061955-A061978.
%K A029514 nonn,base,more
%O A029514 1,2
%A A029514 _Olivier Gérard_
%E A029514 Edited and updated by Larry Reeves (larryr(AT)acm.org), Apr 12 2002
%E A029514 Additional comments and more terms from Larry Reeves (larryr(AT)acm.org), May 25 2001
%E A029514 a(32)-a(37) from _Lars Blomberg_, Oct 11 2011