A328544 Numbers k such that k multiplied by any of its digits contains k as a substring.

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

Offset: 1

Author

N. J. A. Sloane, Oct 19 2019

Keywords

• nonn
• base

Comments

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

Crossrefs

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

Programs

Maple

isA328544 := proc(n)
    local dgs ,d,ndgs,nddgs;
    ndgs := convert(n,base,10) ;
    dgs := convert(ndgs,set) ;
    for d in dgs do
        nddgs := convert(n*d,base,10) ;
        if not verify(ndgs,nddgs,'sublist') then
            return false;
        end if;
    end do:
    true ;
end proc:
for n from 0 do
    if isA328544(n) then
        print(n) ;
    end if;
end do: # R. J. Mathar, Oct 21 2019