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 A266735 #16 Apr 15 2016 15:19:43
%S A266735 1,1,6,90,2520,102011,5176504,307027744,20472135280,1496594831506,
%T A266735 117857270562568,9869468603141427,870255083860881152,
%U A266735 80185525536941657225,7673807618627318341436,759049283017632212000140,77292554293281131959377376,8075621155990277422800518076
%N A266735 Number of words on {1,1,2,2,3,3,...,n,n} avoiding the pattern 12345.
%H A266735 Ferenc Balogh, <a href="http://arxiv.org/abs/1505.01389">A generalization of Gessel's generating function to enumerate words with double or triple occurrences in each letter and without increasing subsequences of a given length</a>, preprint arXiv:1505.01389, 2015.
%H A266735 Shalosh B. Ekhad and Doron Zeilberger, <a href="http://www.math.rutgers.edu/~zeilberg/mamarim/mamarimhtml/sloane75.html">The Generating Functions Enumerating 12..d-Avoiding Words with r occurrences of each of 1,2, ..., n are D-finite for all d and all r</a>, 2014
%Y A266735 Cf. A000680, A220097, A266734.
%Y A266735 Column k=4 of A267479.
%K A266735 nonn
%O A266735 0,3
%A A266735 _N. J. A. Sloane_, Jan 06 2016
%E A266735 More terms from _Alois P. Heinz_, Jan 14 2016