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 A269113 #6 Feb 23 2016 11:55:59 %S A269113 0,0,1,374,173891,117392909,117108036719,171248808285596, %T A269113 360953073372968159,1072323973643442736211,4376906243609822466600689, %U A269113 23919710914189027455648239834,170865299381465355439286870245691,1561721420156259852074018974532765369 %N A269113 Number of sequences with 3 copies each of 1,2,...,n avoiding the pattern 12...n. %H A269113 Alois P. Heinz, <a href="/A269113/b269113.txt">Table of n, a(n) for n = 0..165</a> %F A269113 a(n) = A014606(n) - A047910(n). %Y A269113 Column k=3 of A269129. %Y A269113 Cf. A014606, A047910. %K A269113 nonn %O A269113 0,4 %A A269113 _Alois P. Heinz_, Feb 19 2016