%I #18 Mar 13 2020 11:27:49
%S 1,3,5,7,15,25,55,80,143,187,192,387,1385,1760,4080,9040,9245,15565,
%T 17776,20080,28400,30019,30063,37312,38368,52217,56277,84480,97504,
%U 123040,293045,458560,1258528,2437600,2442000,3122240,7216880
%N Numbers n such that n divides the (right) concatenation of all numbers <= n written in base 21 (most significant digit on right).
%C This sequence differs from A061950 in that all least significant zeros are kept during concatenation.
%C No more terms < 10^7. [_Lars Blomberg_, Oct 11 2011]
%H <a href="/index/N#concat">Index entries for related sequences</a>
%e See A029495 for example.
%t b = 21; c = {}; Select[Range[10^4], Divisible[FromDigits[c = Join[c, Reverse[IntegerDigits[#, b]]], b], #] &] (* _Robert Price_, Mar 13 2020 *)
%Y Cf. A029447-A029470, A029471-A029494, A029495-A029518, A029519-A029542, A061931-A061954, A061955-A061978.
%K nonn,base
%O 1,2
%A _Olivier GĂ©rard_
%E Edited and updated by Larry Reeves (larryr(AT)acm.org), Apr 12 2002
%E Additional comments and more terms from Larry Reeves (larryr(AT)acm.org), May 25 2001
%E a(32)-a(37) from _Lars Blomberg_, Oct 11 2011
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