A061978 - OEIS

A061978

Numbers n such that n divides the (left) concatenation of all numbers <= n written in base 25 (most significant digit on right).

143

%I #16 Mar 09 2020 21:16:15

%S 1,3,9,21,33,57,96,864,1033,1661,6449,6624,10464,68249,81664,108981,

%T 164384,167571,234311,2420409,5490464

%N Numbers n such that n divides the (left) concatenation of all numbers <= n written in base 25 (most significant digit on right).

%C This sequence differs from A029542 in that all least significant zeros are kept during concatenation.

%C No more terms < 7*10^6.

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

%e See A061955 for example.

%t b = 25; c = {}; Select[Range[10^4], Divisible[FromDigits[c = Join[Reverse[IntegerDigits[#, b]], c], b], #] &] (* _Robert Price_, Mar 09 2020 *)

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

%K nonn,base,more

%O 1,2

%A Larry Reeves (larryr(AT)acm.org), May 24 2001

%E Edited and updated by Larry Reeves (larryr(AT)acm.org), Apr 12 2002

%E a(20)-a(21) from _Lars Blomberg_, Jul 22 2011