A029528 - OEIS

%I #25 Nov 13 2021 04:41:37

%S 1,5,20,32,815,1325,5600,7889,34385,138724,897165,1409360,2039049,

%T 2182992,9174075

%N Numbers k such that k divides the (left) concatenation of all numbers <= k written in base 11 (most significant digit on right).

%C This sequence differs from A061964 in that all least significant zeros are removed before concatenation.

%C No more terms < 10^7. - _Lars Blomberg_, Sep 12 2011

%H <a href="/index/N#concat">Index entries for related sequences</a>

%e See A029519 for example.

%t b = 11; c = {}; Select[Range[10^4], Divisible[FromDigits[c = Join[IntegerDigits[IntegerReverse[#, b], b], c], b], #] &] (* _Robert Price_, Mar 13 2020 *)

%o (PARI) lista(nn, m=11) = my(c, s, t); for(k=1, nn, t+=m^c*s=fromdigits(Vecrev(digits(k, m)), m); c+=logint(s, m)+1; if(t%k==0, print1(k, ", "))); \\ _Jinyuan Wang_, Dec 05 2020

%Y Cf. A029447-A029470, A029471-A029494, A029495-A029518, A029519-A029542, A061931-A061954, A061955-A061978.

%K nonn,base,more

%O 1,2

%A _Olivier Gérard_

%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(11)-a(15) from _Lars Blomberg_, Sep 12 2011