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 A220757 #6 Jul 23 2025 01:26:40 %S A220757 16,268,4328,68212,1094438,17553448,281649154,4519836612,72535767418, %T A220757 1164089433866,18681945395446,299818413509296,4811656811358998, %U A220757 77220219019275294,1239274253420409624,19888582401879509716 %N A220757 Number of nX3 arrays of the minimum value of corresponding elements and their horizontal, diagonal or antidiagonal neighbors in a random 0..3 nX3 array. %C A220757 Column 3 of A220761 %H A220757 R. H. Hardin, <a href="/A220757/b220757.txt">Table of n, a(n) for n = 1..110</a> %F A220757 Empirical: a(n) = 18*a(n-1) -21*a(n-2) -138*a(n-3) -441*a(n-4) -137*a(n-5) +1764*a(n-6) -1136*a(n-7) +14709*a(n-8) +67123*a(n-9) +121526*a(n-10) -80625*a(n-11) -792044*a(n-12) -1086870*a(n-13) -773840*a(n-14) -232356*a(n-15) -156248*a(n-16) -229216*a(n-17) -86528*a(n-18) %e A220757 Some solutions for n=3 %e A220757 ..1..0..1....3..1..1....0..0..1....0..0..0....3..0..0....1..1..1....2..0..2 %e A220757 ..0..0..2....2..1..2....0..0..2....2..0..1....3..0..2....2..0..2....3..0..0 %e A220757 ..3..0..3....2..2..3....0..0..1....1..1..1....2..2..3....0..0..0....0..0..3 %K A220757 nonn %O A220757 1,1 %A A220757 _R. H. Hardin_ Dec 19 2012