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 A268454 #4 Feb 04 2016 22:02:31 %S A268454 6,36,211,1231,7160,41526,240170,1385338,7970326,45742764,261899866, %T A268454 1496074920,8527336280,48500972230,275294704851,1559507239653, %U A268454 8817578095886,49763675574292,280352403988287,1576707102660739 %N A268454 Number of length-n 0..5 arrays with no adjacent pair x,x+1 followed at any distance by x+1,x. %C A268454 Column 5 of A268457. %H A268454 R. H. Hardin, <a href="/A268454/b268454.txt">Table of n, a(n) for n = 1..210</a> %H A268454 R. H. Hardin, <a href="/A268454/a268454.txt">Empirical recurrence of order 51</a> %F A268454 Empirical recurrence of order 51 (see link above) %e A268454 Some solutions for n=6 %e A268454 ..4....1....1....0....5....2....5....4....1....4....5....3....0....4....5....0 %e A268454 ..0....5....0....0....5....1....5....2....4....5....2....3....2....2....4....4 %e A268454 ..3....2....0....0....5....5....4....2....0....3....4....5....3....3....0....5 %e A268454 ..5....3....5....2....0....5....2....4....0....2....3....0....5....0....5....1 %e A268454 ..0....4....4....3....1....1....5....4....4....1....2....4....2....2....1....1 %e A268454 ..4....0....5....4....1....1....0....1....4....1....4....2....1....4....0....3 %Y A268454 Cf. A268457. %K A268454 nonn %O A268454 1,1 %A A268454 _R. H. Hardin_, Feb 04 2016