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 A269120 #6 Mar 02 2016 21:05:16 %S A269120 0,0,1,1004849563,7541872062618216079,370243779118368267931211789686, %T A269120 91050643996464879303067913358954122530151, %U A269120 90098061524165913059428708258834814271005531460359720,302407545158616421950876578542740909974755462890611522604756347847 %N A269120 Number of sequences with 10 copies each of 1,2,...,n avoiding the pattern 12...n. %H A269120 Alois P. Heinz, <a href="/A269120/b269120.txt">Table of n, a(n) for n = 0..60</a> %F A269120 a(n) = (10*n)!/10!^n - A268853(n). %Y A269120 Column k=10 of A269129. %Y A269120 Cf. A268853. %K A269120 nonn %O A269120 0,4 %A A269120 _Alois P. Heinz_, Feb 19 2016