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 A268014 #6 May 04 2021 14:04:12 %S A268014 9,81,729,6084,49284,386884,2965284,22268961,164378041,1195430625, %T A268014 8581613769,60904316944,427872974400,2978730810000,20567785069584, %U A268014 140966727989481,959632952511249,6492348190361881,43674091151207841 %N A268014 Number of n X 2 0..2 arrays with every repeated value in every row and column greater than or equal to the previous repeated value. %C A268014 Column 2 of A268019. %H A268014 R. H. Hardin, <a href="/A268014/b268014.txt">Table of n, a(n) for n = 1..210</a> %F A268014 Empirical: a(n) = 25*a(n-1) -225*a(n-2) +745*a(n-3) +475*a(n-4) -6275*a(n-5) -885*a(n-6) +22525*a(n-7) +22525*a(n-8) -885*a(n-9) -6275*a(n-10) +475*a(n-11) +745*a(n-12) -225*a(n-13) +25*a(n-14) -a(n-15). %e A268014 Some solutions for n=5 %e A268014 ..1..1....0..2....2..1....1..1....1..1....1..0....0..2....1..0....1..0....2..1 %e A268014 ..2..2....0..2....2..2....0..1....2..2....0..0....2..2....0..0....2..0....0..0 %e A268014 ..0..1....1..0....2..0....1..1....1..1....2..2....0..1....1..0....0..1....0..2 %e A268014 ..1..0....2..1....1..0....1..1....0..1....0..2....1..2....1..2....2..2....0..1 %e A268014 ..0..2....2..0....2..0....2..0....1..0....1..2....0..0....0..0....2..0....0..2 %Y A268014 Cf. A268019. %K A268014 nonn %O A268014 1,1 %A A268014 _R. H. Hardin_, Jan 24 2016