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 A280960 #4 Jan 11 2017 15:16:55 %S A280960 224,23593,402077,9986376,251270618,6052621154,148137367471, %T A280960 3624578433814,88500510514256,2162800206884214,52848406746190667, %U A280960 1291317121466531838,31553229218022226192,770996700142671487457 %N A280960 Number of nX7 0..2 arrays with no element equal to more than one of its horizontal, vertical and antidiagonal neighbors and with new values introduced in order 0 sequentially upwards. %C A280960 Column 7 of A280961. %H A280960 R. H. Hardin, <a href="/A280960/b280960.txt">Table of n, a(n) for n = 1..62</a> %e A280960 Some solutions for n=2 %e A280960 ..0..1..2..0..2..1..2. .0..1..2..0..1..0..2. .0..1..0..1..2..1..0 %e A280960 ..0..2..1..2..0..2..0. .2..0..1..0..1..0..1. .0..1..2..0..2..0..2 %Y A280960 Cf. A280961. %K A280960 nonn %O A280960 1,1 %A A280960 _R. H. Hardin_, Jan 11 2017