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 A209106 #7 Jul 22 2025 21:38:51 %S A209106 365,254496,125526240,57113932788,25586970618660,11437585318270860, %T A209106 5112092569118325704,2285013663964828552960,1021387683873603848380972, %U A209106 456557468966590708568722520,204080223921705625484844604564 %N A209106 Number of 7Xn 0..2 arrays with new values 0..2 introduced in row major order and no element equal to more than one of its immediate leftward or upward or right-upward antidiagonal neighbors. %C A209106 Row 7 of A209100 %H A209106 R. H. Hardin, <a href="/A209106/b209106.txt">Table of n, a(n) for n = 1..158</a> %e A209106 Some solutions for n=4 %e A209106 ..0..1..0..2....0..1..0..2....0..0..0..0....0..0..0..1....0..0..0..1 %e A209106 ..1..2..0..1....2..2..0..1....1..1..1..1....1..2..2..1....2..1..2..2 %e A209106 ..1..0..1..2....0..1..2..1....2..2..0..1....2..0..1..2....0..2..0..0 %e A209106 ..0..1..2..0....2..1..0..1....0..2..1..0....2..1..2..0....2..0..1..1 %e A209106 ..0..2..0..1....1..2..2..2....1..2..0..1....1..2..0..1....2..1..2..1 %e A209106 ..0..1..2..0....1..0..0..0....2..0..1..0....1..2..0..2....2..1..0..2 %e A209106 ..1..2..0..1....0..1..2..1....0..1..2..0....2..0..1..2....1..2..1..2 %K A209106 nonn %O A209106 1,1 %A A209106 _R. H. Hardin_ Mar 05 2012