A061974 Numbers n such that n divides the (left) concatenation of all numbers <= n written in base 21 (most significant digit on right).
1, 5, 25, 125, 155, 160, 421, 1409, 729175, 2804576
Offset: 1
Examples
See A061955 for example.
Crossrefs
Programs
-
Mathematica
b = 21; c = {}; Select[Range[10^4], Divisible[FromDigits[c = Join[Reverse[IntegerDigits[#, b]], c], b], #] &] (* Robert Price, Mar 09 2020 *) -
PARI
lista(nn, m=21) = my(c, t); for(k=1, nn, t+=m^c*fromdigits(Vecrev(digits(k, m)), m); c+=logint(m*k, m); if(t%k==0, print1(k, ", "))); \\ Jinyuan Wang, Dec 05 2020
Extensions
Edited and updated by Larry Reeves (larryr(AT)acm.org), Apr 12 2002
a(9)-a(10) from Lars Blomberg, Jul 27 2011
Comments