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Smallest number m such that m and the product of digits of m are both divisible by 3n, or 0 if no such number exists.
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%I #19 Jan 26 2020 16:58:48

%S 3,6,9,168,135,36,273,168,999,0,0,1296,0,378,495,384,0,1296,0,0,1197,

%T 0,0,1368,3525,0,2997,672,0,0,0,384,0,0,735,1296,0,0,0,0,0,3276,0,0,

%U 3915,0,0,3168,7497,0,0,0,0,5994,0,7896,0,0,0,0,0,0,7938,2688,0,0,0,0,0,0,0

%N Smallest number m such that m and the product of digits of m are both divisible by 3n, or 0 if no such number exists.

%C Here 0 is regarded as not divisible by any number.

%C a(n) = 0 if 10 divides 3n or n contains a prime divisor > 9. - _Sascha Kurz_, Aug 23 2002

%H Robert Israel, <a href="/A073910/b073910.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A085124(3*n). - _R. J. Mathar_, Jun 21 2018

%p f := 3:for i from 1 to 1000 do b := ifactors(f*i)[2]: if b[nops(b)][1]>9 or (f*i mod 10) =0 then a[i] := 0:else j := 0:while true do j := j+f*i:c := convert(j,base,10):d := product(c[k],k=1..nops(c)): if (d mod f*i)=0 and d>0 then a[i] := j:break:fi:od:fi:od:seq(a[k],k=1..1000);

%Y Cf. A073906, A073908, A073909, A073911, A073912, A085124.

%K nonn,base

%O 1,1

%A _Amarnath Murthy_, Aug 18 2002

%E More terms from _Sascha Kurz_, Aug 23 2002