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 A268961 #4 Feb 16 2016 11:55:33 %S A268961 23,1361,24714,272738,2355975,18146537,134520386,1002621328, %T A268961 7680218714,60997066270,503350821180,4313327580676,38328122520204, %U A268961 352617973045358,3353662534979250,32927372167566264,333319728382967773 %N A268961 Number of length-(n+7) 0..n arrays with no repeated value equal to the previous repeated value, with new values introduced in sequential order. %C A268961 Subdiagonal 7 of A268956. %H A268961 R. H. Hardin, <a href="/A268961/b268961.txt">Table of n, a(n) for n = 1..115</a> %e A268961 Some solutions for n=3 %e A268961 ..0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0 %e A268961 ..1. .1. .1. .1. .1. .1. .1. .1. .0. .1. .1. .1. .1. .1. .1. .0 %e A268961 ..1. .2. .2. .2. .2. .0. .2. .2. .1. .0. .2. .0. .1. .0. .0. .1 %e A268961 ..2. .0. .3. .3. .2. .0. .3. .0. .0. .2. .0. .0. .2. .2. .2. .2 %e A268961 ..1. .2. .2. .1. .0. .2. .2. .3. .2. .2. .2. .1. .1. .3. .2. .0 %e A268961 ..0. .0. .1. .1. .1. .2. .1. .0. .2. .3. .0. .2. .0. .0. .3. .3 %e A268961 ..1. .1. .0. .0. .3. .1. .1. .0. .0. .1. .0. .0. .3. .2. .0. .0 %e A268961 ..2. .1. .3. .0. .3. .2. .2. .2. .2. .0. .2. .1. .2. .3. .0. .3 %e A268961 ..2. .2. .3. .1. .2. .0. .2. .3. .1. .1. .0. .2. .2. .2. .3. .3 %e A268961 ..0. .2. .2. .1. .3. .3. .3. .0. .3. .0. .1. .3. .3. .1. .2. .0 %Y A268961 Cf. A268956. %K A268961 nonn %O A268961 1,1 %A A268961 _R. H. Hardin_, Feb 16 2016