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 A218520 #6 Jul 22 2025 23:57:40 %S A218520 236,42812,7687526,1326731972,232640291710,40522780697742, %T A218520 7051080210074740,1226141540661411646,213181725321313805184, %U A218520 37062512930409971808074,6443364732821356673971218 %N A218520 Number of nX6 arrays of the minimum value of corresponding elements and their horizontal or antidiagonal neighbors in a random 0..3 nX6 array. %C A218520 Column 6 of A218522 %H A218520 R. H. Hardin, <a href="/A218520/b218520.txt">Table of n, a(n) for n = 1..67</a> %e A218520 Some solutions for n=3 %e A218520 ..0..0..0..1..3..2....0..0..0..0..3..3....0..0..0..1..1..3....0..0..0..1..3..3 %e A218520 ..0..0..0..1..1..1....0..0..0..1..0..0....0..0..1..3..0..3....0..0..1..3..2..2 %e A218520 ..0..0..1..1..0..0....0..0..3..3..0..2....1..3..0..0..0..0....0..0..3..2..2..2 %K A218520 nonn %O A218520 1,1 %A A218520 _R. H. Hardin_ Oct 31 2012