cp's OEIS Frontend

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.

A061943 Numbers n such that n divides the (right) concatenation of all numbers <= n written in base 14 (most significant digit on right).

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%I A061943 #19 Dec 05 2020 06:36:22
%S A061943 1,2,6,7,10,13,39,45,65,131,195,1690,2005,2106,3211,11615,18498,20881,
%T A061943 22360,36335,104858,234506,665223,1274944,1328487,1425268,2305498
%N A061943 Numbers n such that n divides the (right) concatenation of all numbers <= n written in base 14 (most significant digit on right).
%C A061943 This sequence differs from A029507 in that all least significant zeros are removed before concatenation.
%C A061943 No more terms < 10^7. - _Lars Blomberg_, Oct 22 2011
%H A061943 <a href="/index/N#concat">Index entries for related sequences</a>
%e A061943 See A061931 for example.
%t A061943 b = 14; c = {}; Select[Range[10^4], Divisible[FromDigits[c = Join[c, IntegerDigits[IntegerReverse[#, b], b]], b], #] &] (* _Robert Price_, Mar 08 2020 *)
%o A061943 (PARI) lista(nn, m=14) = 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 A061943 Cf. A029447-A029470, A029471-A029494, A029495-A029518, A029519-A029542, A061931-A061954, A061955-A061978.
%K A061943 nonn,base,more
%O A061943 1,2
%A A061943 Larry Reeves (larryr(AT)acm.org), May 24 2001
%E A061943 Edited and updated by Larry Reeves (larryr(AT)acm.org), Apr 12 2002
%E A061943 a(23)-a(27) from _Lars Blomberg_, Oct 22 2011