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Number of zeros in decimal representation of 1001^n.
1

%I #6 Nov 21 2013 12:48:21

%S 0,2,4,6,8,10,10,10,12,10,12,8,8,6,18,14,10,10,8,5,12,14,9,7,10,18,14,

%T 13,15,13,15,10,14,12,17,16,17,15,13,21,24,15,9,16,12,22,20,21,20,16,

%U 19,16,21,20,25,20,20,21,26,19,20,19,22,19,17,23,28,24,22,20,27,26,25

%N Number of zeros in decimal representation of 1001^n.

%C a(n) = A055641(A097659(n)).

%e a(2)=4, as A097659(1)=1001^2=1002001 contains four zeros.

%t DigitCount[#,10,0]&/@(1001^Range[0,75]) (* _Harvey P. Dale_, Apr 26 2011 *)

%K nonn,base

%O 0,2

%A _Reinhard Zumkeller_, Aug 18 2004