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 A204628 #7 Jul 22 2025 18:11:20 %S A204628 393216,425257068,459972403614,497525810748759,538145459458960020, %T A204628 582081449451902347866,629604521519860258105194, %U A204628 681007535879068229405338152,736607263887839663637635211744 %N A204628 Number of (n+1)X7 0..2 arrays with every 2X2 subblock having unequal diagonal elements or unequal antidiagonal elements, and new values 0..2 introduced in row major order. %C A204628 Column 6 of A204630 %H A204628 R. H. Hardin, <a href="/A204628/b204628.txt">Table of n, a(n) for n = 1..210</a> %e A204628 Some solutions for n=3 %e A204628 ..0..1..0..2..1..2..2....0..0..0..0..0..0..0....0..1..0..1..1..1..1 %e A204628 ..1..1..0..1..1..0..0....1..1..1..0..1..2..2....1..1..0..0..1..2..1 %e A204628 ..2..0..0..2..0..0..1....1..0..1..1..1..0..2....0..2..1..0..2..2..1 %e A204628 ..1..2..0..1..2..2..0....0..0..0..0..1..1..0....0..2..2..2..1..2..0 %K A204628 nonn %O A204628 1,1 %A A204628 _R. H. Hardin_ Jan 17 2012