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 A219880 #6 Jul 23 2025 00:45:38 %S A219880 15,24,292,2190,14536,89795,565824,3605746,22430565,132945658, %T A219880 747855900,4015816403,20719013269,103153843621,496871314897, %U A219880 2319802248962,10515430463734,46349614135168,198938106785464,832494580725450 %N A219880 Number of nX5 arrays of the minimum value of corresponding elements and their horizontal, diagonal or antidiagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and nonincreasing columns, 0..2 nX5 array. %C A219880 Column 5 of A219883 %H A219880 R. H. Hardin, <a href="/A219880/b219880.txt">Table of n, a(n) for n = 1..23</a> %e A219880 Some solutions for n=3 %e A219880 ..1..0..0..0..0....1..1..0..0..0....2..2..1..1..1....2..2..1..0..0 %e A219880 ..1..0..0..0..0....1..1..0..0..0....2..2..1..1..1....2..2..1..0..1 %e A219880 ..1..0..1..0..0....2..1..1..1..2....2..2..2..1..2....2..2..2..2..2 %K A219880 nonn %O A219880 1,1 %A A219880 _R. H. Hardin_ Nov 30 2012