login
Smallest number k such that kn contains two consecutive digits which are the same.
2

%I #6 May 04 2013 10:09:08

%S 11,11,11,11,11,11,11,11,11,10,1,12,9,8,15,7,7,8,6,5,16,1,5,6,4,13,37,

%T 4,4,10,5,7,1,13,13,4,3,3,3,5,13,8,8,1,5,7,4,3,9,2,5,17,9,21,1,2,2,2,

%U 2,5,2,9,7,7,7,1,5,8,8,10,5,2,7,3,3,3,1,15,7,5,14,13,2,4,3,4,6,1,5,10,5

%N Smallest number k such that kn contains two consecutive digits which are the same.

%t snk[n_]:=Module[{k=1},While[!MemberQ[Differences[IntegerDigits[k*n]],0], k++]; k]; Array[snk, 100] (* _Harvey P. Dale_, May 04 2013 *)

%K base,nonn

%O 1,1

%A _Erich Friedman_