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 A267971 #5 Jan 23 2016 09:59:51 %S A267971 64,4096,216000,10941048,519718464,23689358848,1040125019968, %T A267971 44297983526887,1837365396992000,74486671360299008, %U A267971 2959536976199968256,115510695146966939968,4436989542752316253696,167999383203780355895296 %N A267971 Number of nX3 0..3 arrays with every repeated value in every row greater than or equal to, and in every column greater than, the previous repeated value. %C A267971 Column 3 of A267974. %H A267971 R. H. Hardin, <a href="/A267971/b267971.txt">Table of n, a(n) for n = 1..210</a> %H A267971 R. H. Hardin, <a href="/A267971/a267971.txt">Empirical recurrence of order 40</a> %F A267971 Empirical recurrence of order 40 (see link above) %e A267971 Some solutions for n=2 %e A267971 ..0..3..2....0..1..2....2..1..3....3..2..3....3..2..1....2..3..0....3..1..3 %e A267971 ..0..3..2....1..1..0....3..2..3....2..0..1....3..1..2....3..3..1....1..0..0 %Y A267971 Cf. A267974. %K A267971 nonn %O A267971 1,1 %A A267971 _R. H. Hardin_, Jan 23 2016