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 A069530 Smallest multiple of n with digit sum = 11, or 0 if no such number exists. 13

%I

%S 29,38,0,56,65,0,56,56,0,290,209,0,65,56,0,128,119,0,38,380,0,308,92,

%T 0,425,182,0,56,29,0,155,128,0,272,245,0,74,38,0,560,164,0,344,308,0,

%U 92,47,0,245,650,0,416,371,0,605,56,0,290,236,0,1037,434,0,128,65,0,335

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

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

%F a(n) = n*A088400(n). - _R. J. Mathar_, Aug 06 2019

%p A069530 := proc(n)

%p local m ;

%p if modp(n,3) = 0 then

%p 0 ;

%p else

%p for m from 1 do

%p if digsum(m*n) = 11 then

%p return m*n ;

%p end if;

%p end do:

%p end if;

%p end proc:

%p seq(A069530(n),n=1..70) ; # _R. J. Mathar_, Aug 06 2019

%o (PARI) sod(n) = {digs = digits(n); return (sum(i=1, #digs, digs[i]));}

%o a(n) = {if (n % 3 == 0, return (0)); k = 1; while (sod(k*n) != 11, k++); k;} \\ _Michel Marcus_, Sep 14 2013

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

%K base,nonn

%O 1,1

%A _Amarnath Murthy_, Apr 01 2002

%E More terms from _Sascha Kurz_, Apr 08 2002

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Last modified September 16 06:38 EDT 2019. Contains 327090 sequences. (Running on oeis4.)