A328544 - OEIS

%I #7 Oct 21 2019 13:54:49

%S 0,1,5,6,11,111,1111,11111,111111

%N Numbers k such that k multiplied by any of its digits contains k as a substring.

%C Conjecture: consists of 0,5,6, and the numbers 11...1.

%p isA328544 := proc(n)

%p     local dgs ,d,ndgs,nddgs;

%p     ndgs := convert(n,base,10) ;

%p     dgs := convert(ndgs,set) ;

%p     for d in dgs do

%p         nddgs := convert(n*d,base,10) ;

%p         if not verify(ndgs,nddgs,'sublist') then

%p             return false;

%p         end if;

%p     end do:

%p     true ;

%p end proc:

%p for n from 0 do

%p     if isA328544(n) then

%p         print(n) ;

%p     end if;

%p end do: # _R. J. Mathar_, Oct 21 2019

%Y Suggested by A328095 (which is a much more interesting sequence).

%K nonn,base

%O 1,3

%A _N. J. A. Sloane_, Oct 19 2019