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 A218133 #6 Dec 11 2014 04:14:43 %S A218133 0,0,990,58800,1047540,9762480,60458370,282458400,1073709000, %T A218133 3486725280,9999899910,25937263440,61917115260,137858120400, %U A218133 289254116970,576649631040,1099510578960,2015992480320,3570465336750,6131063781360,10239996799620,16679876893680 %N A218133 Number of length 10 primitive (=aperiodic or period 10) n-ary words. %H A218133 Alois P. Heinz, <a href="/A218133/b218133.txt">Table of n, a(n) for n = 0..1000</a> %F A218133 G.f.: -30 *(x+1) *x^2 *(35*x^6 +1556*x^5 +13619*x^4 +30064*x^3 +13609*x^2 +1564*x +33) / (x-1)^11. %F A218133 a(n) = n^10-n^5-n^2+n. %p A218133 a:= n-> (((n^5-1)*n^3-1)*n+1)*n: %p A218133 seq(a(n), n=0..30); %Y A218133 Row n=10 of A143324. %K A218133 nonn,easy %O A218133 0,3 %A A218133 _Alois P. Heinz_, Oct 21 2012