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 A268960 #4 Feb 16 2016 11:54:53 %S A268960 15,525,6723,58409,426289,2918103,19899645,139354433,1014707218, %T A268960 7708112426,61057289906,503473697674,4313566395798,38328567460364, %U A268960 352618771825166,3353663922642364,32927374508631249,333319732229912935 %N A268960 Number of length-(n+6) 0..n arrays with no repeated value equal to the previous repeated value, with new values introduced in sequential order. %C A268960 Subdiagonal 6 of A268956. %H A268960 R. H. Hardin, <a href="/A268960/b268960.txt">Table of n, a(n) for n = 1..116</a> %e A268960 Some solutions for n=4 %e A268960 ..0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0 %e A268960 ..1. .1. .1. .1. .1. .1. .1. .1. .1. .1. .1. .1. .1. .1. .1. .1 %e A268960 ..0. .2. .0. .2. .1. .2. .2. .2. .2. .2. .2. .1. .0. .0. .2. .1 %e A268960 ..2. .3. .1. .2. .2. .1. .1. .2. .0. .0. .3. .2. .2. .2. .1. .0 %e A268960 ..2. .2. .2. .3. .2. .0. .2. .3. .1. .1. .1. .0. .0. .3. .0. .2 %e A268960 ..3. .3. .1. .3. .3. .3. .0. .0. .3. .2. .1. .1. .2. .1. .2. .0 %e A268960 ..0. .1. .3. .0. .4. .2. .3. .2. .3. .3. .4. .2. .3. .0. .2. .2 %e A268960 ..2. .3. .0. .3. .2. .2. .0. .0. .1. .4. .3. .1. .1. .1. .3. .2 %e A268960 ..1. .3. .4. .4. .3. .0. .2. .2. .4. .4. .3. .2. .4. .1. .4. .3 %e A268960 ..2. .0. .2. .3. .4. .2. .3. .4. .1. .1. .1. .2. .3. .0. .1. .1 %Y A268960 Cf. A268956. %K A268960 nonn %O A268960 1,1 %A A268960 _R. H. Hardin_, Feb 16 2016