A029530 - OEIS

%I #23 Jul 26 2021 01:46:58

%S 1,3,9,24,48,80,96,184,549,1083,1392,1624,5085,15968,16000,17763,

%T 144843,156200,695808,854904,1001808,1960016,2002776,2961952

%N Numbers k such that k divides the (left) concatenation of all numbers <= k written in base 13 (most significant digit on right).

%C This sequence differs from A061966 in that all least significant zeros are removed before concatenation.

%C No more terms < 10^7. - _Lars Blomberg_, Sep 15 2011

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

%e See A029519 for example.

%t b = 13; 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=13) = 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(19)-a(24) from _Lars Blomberg_, Sep 15 2011