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 A181578 #6 Mar 31 2012 10:26:16 %S A181578 0,1,2,3,4,0,5,6,7,8,9,0,10,11,12,13,14,0,15,16,17,18,19,0,20,21,22, %T A181578 23,24,0,0,25,26,27,28,29,0,30,31,32,33,34,0,35,36,37,38,39,0,40,41, %U A181578 42,43,44,0,45,46,47,48,49,0,0,50,51,52,53,54,0,55,56,57,58,59,0,60,61,62,63 %N A181578 The number k such that each of the five factorials (5k+j)!, j=0..4, has exactly n trailing zeros in its base-10 representation; 0 if no such k exists. %C A181578 Entries are zero if n is an element of A000966. %C A181578 This traces 5 consecutive occurrences of n in A027868. %Y A181578 Cf. A181579, A000142. %K A181578 nonn,base %O A181578 0,3 %A A181578 _Lekraj Beedassy_, Nov 02 2010