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 A209017 #7 Jul 22 2025 21:34:59 %S A209017 972,1901964,3707858104,7224768704460,14081479775124768, %T A209017 27444816617702590210,53490209804089514438574, %U A209017 104252853354306374638934760,203189693440653459494447382012 %N A209017 Number of nX6 0..3 arrays with no element equal the average of immediate neighbors vertically above, diagonally above and left, and horizontally left of it. %C A209017 Column 6 of A209019 %H A209017 R. H. Hardin, <a href="/A209017/b209017.txt">Table of n, a(n) for n = 1..210</a> %e A209017 Some solutions for n=4 %e A209017 ..3..0..2..0..2..3....1..0..2..3..2..1....0..2..0..3..0..1....0..1..2..3..0..3 %e A209017 ..0..0..0..0..3..2....2..0..3..3..0..2....2..1..2..0..2..2....3..0..2..0..2..2 %e A209017 ..1..2..3..2..3..3....0..0..3..2..3..1....0..2..0..2..2..1....1..1..0..0..1..0 %e A209017 ..2..3..0..0..1..2....1..2..0..1..0..0....1..3..1..0..1..0....3..2..2..1..0..0 %K A209017 nonn %O A209017 1,1 %A A209017 _R. H. Hardin_ Mar 04 2012