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 A269122 #12 Mar 11 2016 12:07:11 %S A269122 1,23,1879,173891,16140983,1474050783,132279480115,11690616534627, %T A269122 1020149742404727,88094027572412735,7541872062618216079, %U A269122 641058122723345275763,54163773797158984485203,4553249681522845632696611,381122944171897823109474291 %N A269122 Number of sequences with n copies each of 1,2,3,4 avoiding the pattern 1234. %H A269122 Alois P. Heinz, <a href="/A269122/b269122.txt">Table of n, a(n) for n = 0..525</a> %F A269122 a(n) = A008977(n) - A268840(n). %Y A269122 Row n=4 of A269129. %Y A269122 Cf. A008977, A268840. %K A269122 nonn %O A269122 0,2 %A A269122 _Alois P. Heinz_, Feb 19 2016