%I A051802
%S A051802 1,1,2,3,4,5,6,7,8,9,1,1,2,3,4,5,6,7,8,9,2,2,4,6,8,1,2,4,6,8,3,3,6,9,2,
%T A051802 5,8,2,8,4,4,4,8,2,6,2,8,6,6,8,5,5,1,5,2,1,3,5,4,2,6,6,2,8,8,3,8,8,6,2,
%U A051802 7,7,4,2,6,5,8,8,3,8,8,8,6,8,6,4,6,3,8,4,9,9,8,4,8,2,2,8,4,8,1,1,2,3,4
%N A051802 Nonzero multiplicative digital root of n.
%D A051802 Discussed Jun 15 1991 on sci.math by Mayne, Rusin, Landrum et al.
%H A051802 T. D. Noe, <a href="b051802.txt">Table of n, a(n) for n=0..1000</a>
%F A051802 If n==A051801(n) then n else a(A051801(n)).
%t A051802 mdr0[n_] := NestWhile[Times @@ (IntegerDigits@# /. 0 -> 1) &, n, UnsameQ, 
               All]; Table[ mdr0@n, {n, 0, 104}] - Robert G. Wilson v (rgwv(at)rgwv.com), 
               Aug 04 2006
%Y A051802 Uses A051801.
%Y A051802 Sequence in context: A054055 A067456 A052429 this_sequence A051801 A071205 
               A066750
%Y A051802 Adjacent sequences: A051799 A051800 A051801 this_sequence A051803 A051804 
               A051805
%K A051802 nonn,easy,base,nice
%O A051802 0,3
%A A051802 Dan Hoey (Hoey(AT)AIC.NRL.Navy.Mil), Dec 09 1999
%E A051802 Occasionally defined with a(0)=0.
%E A051802 More terms from Robert G. Wilson v (rgwv(at)rgwv.com), Aug 04 2006