This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A097660 #6 Nov 21 2013 12:48:21 %S A097660 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 A097660 13,15,13,15,10,14,12,17,16,17,15,13,21,24,15,9,16,12,22,20,21,20,16, %U A097660 19,16,21,20,25,20,20,21,26,19,20,19,22,19,17,23,28,24,22,20,27,26,25 %N A097660 Number of zeros in decimal representation of 1001^n. %C A097660 a(n) = A055641(A097659(n)). %e A097660 a(2)=4, as A097659(1)=1001^2=1002001 contains four zeros. %t A097660 DigitCount[#,10,0]&/@(1001^Range[0,75]) (* _Harvey P. Dale_, Apr 26 2011 *) %K A097660 nonn,base %O A097660 0,2 %A A097660 _Reinhard Zumkeller_, Aug 18 2004