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 A278307 #4 Nov 17 2016 07:06:52 %S A278307 266,51562,11557658,2506281752,507575149862,100825279690194, %T A278307 20065923383306483,3886257287342627627,704764955038032952712, %U A278307 117079743963382645853885,17705807900846493728558253 %N A278307 Number of nX6 0..2 arrays with rows and columns in lexicographic nondecreasing order but with exactly one mistake. %C A278307 Column 6 of A278309. %H A278307 R. H. Hardin, <a href="/A278307/b278307.txt">Table of n, a(n) for n = 1..45</a> %e A278307 Some solutions for n=2 %e A278307 ..0..0..1..1..2..0. .0..0..0..1..0..1. .0..0..1..1..0..2. .0..0..0..1..0..2 %e A278307 ..1..2..1..2..2..0. .0..1..2..2..1..0. .1..1..0..2..2..1. .0..0..1..2..2..1 %Y A278307 Cf. A278309. %K A278307 nonn %O A278307 1,1 %A A278307 _R. H. Hardin_, Nov 17 2016