A069530 Smallest multiple of n with digit sum = 11, or 0 if no such number exists.

29, 38, 0, 56, 65, 0, 56, 56, 0, 290, 209, 0, 65, 56, 0, 128, 119, 0, 38, 380, 0, 308, 92, 0, 425, 182, 0, 56, 29, 0, 155, 128, 0, 272, 245, 0, 74, 38, 0, 560, 164, 0, 344, 308, 0, 92, 47, 0, 245, 650, 0, 416, 371, 0, 605, 56, 0, 290, 236, 0, 1037, 434, 0, 128, 65, 0, 335

Offset: 1

Author

Amarnath Murthy, Apr 01 2002

Keywords

• base
• nonn

Comments

a(n) = 0 if n is divisible by 3, 1111, 1507, 2849, 3367, 4849, 5291 or 7373. - Robert Israel, Feb 14 2024

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A166311, A069521, A069522, A069523, A069524, A069525, A069526, A069527, A069528, A069529.

Programs

Maple

A069530 := proc(n)
    local m ;
    if modp(n,3) = 0 then
         0 ;
    else
        for m from 1 do
            if digsum(m*n) = 11 then
                return m*n ;
            end if;
        end do:
    end if;
end proc:
seq(A069530(n),n=1..70) ; # R. J. Mathar, Aug 06 2019

PARI

sod(n) = {digs = digits(n); return (sum(i=1, #digs, digs[i]));}
a(n) = {if (n % 3 == 0, return (0)); k = 1; while (sod(k*n) != 11, k++); k;} \\ Michel Marcus, Sep 14 2013

Formula

a(3k) = 0 for k = 1, 2, 3, ....

a(n) = n*A088400(n). - R. J. Mathar, Aug 06 2019

Extensions

More terms from Sascha Kurz, Apr 08 2002