A147826 - OEIS

%I #13 Mar 21 2016 03:13:21

%S 0,6,24,33,222,1599,3333,11427,87486,111111,6999999,6090909,24999999,

%T 69076923,357142857,3333333333,6249999993,29411764647,111111111111,

%U 421047368421,24999999999999,9047619047619,159090909090909,217391304347826,1666666666666662,15999999999999999

%N Minimum number k for which the digital sum of k*n is 6*n.

%H Chai Wah Wu, <a href="/A147826/b147826.txt">Table of n, a(n) for n = 0..39</a>

%p P:=proc(i) local j,k,n,ok,w; for n from 0 by 1 to i do j:=-1; ok:=1; while ok=1 do j:=j+1; w:=0; k:=n*j; while k>0 do w:=w+k-(trunc(k/10)*10); k:=trunc(k/10); od; if w=6*n then ok:=0; print(j); fi; od; od; end: P(100);

%o (PARI) a(n) = {my(k = 0); while (sumdigits(k*n) != 6*n, k++); k;}; \\ _Michel Marcus_, Mar 21 2016

%Y Cf. A147822-A147825, A147827-A147831.

%K easy,nonn,base

%O 0,2

%A _Paolo P. Lava_ and _Giorgio Balzarotti_, Nov 14 2008

%E Edited by _Charles R Greathouse IV_, Nov 01 2009

%E a(10)-a(19) from _Donovan Johnson_, Sep 16 2012

%E a(20)-a(25) from _Chai Wah Wu_, Mar 20 2016