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 A267995 #9 Mar 21 2025 22:07:10 %S A267995 250,62500,15625000,3552627426,766970396055,158016399692284, %T A267995 31323853192497584,6008048043198865162,1120010376077692767415, %U A267995 203652957857164291693586,36224276466386619972386421,6318133327227578310005800855,1082746870173375929870886556128,182620177616634763310401464884566 %N A267995 Number of n X 4 0..3 arrays with every repeated value in every row and column greater than or equal to the previous repeated value. %H A267995 R. H. Hardin, <a href="/A267995/b267995.txt">Table of n, a(n) for n = 1..41</a> %e A267995 Some solutions for n=2: %e A267995 ..2..3..1..0....1..1..3..3....0..0..0..1....0..1..3..1....1..2..3..3 %e A267995 ..2..0..0..1....1..1..0..3....1..3..0..2....1..3..3..1....0..1..1..1 %Y A267995 Column 4 of A267997. %K A267995 nonn %O A267995 1,1 %A A267995 _R. H. Hardin_, Jan 24 2016