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 A267975 #8 Feb 26 2018 08:21:53 %S A267975 4,16,64,250,964,3674,13868,51917,192980,712868,2618876,9573915, %T A267975 34845780,126322410,456285828,1642687662,5895922368,21102304252, %U A267975 75332038300,268275675007,953247943192,3380004168904,11961143709736,42249741430325 %N A267975 Number of 1 X n 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 A267975 Row 1 of A267974. %H A267975 R. H. Hardin, <a href="/A267975/b267975.txt">Table of n, a(n) for n = 1..210</a> %F A267975 Empirical: a(n) = 12*a(n-1) - 50*a(n-2) + 72*a(n-3) + 21*a(n-4) - 72*a(n-5) - 50*a(n-6) - 12*a(n-7) -a(n-8). %F A267975 Empirical g.f.: x*(4 - 32*x + 72*x^2 - 6*x^3 - 72*x^4 - 50*x^5 - 12*x^6 - x^7) / (1 - 3*x - x^2)^4. - _Colin Barker_, Feb 26 2018 %e A267975 Some solutions for n=8: %e A267975 ..0..0..3..1..1..2..2..1....3..2..0..1..3..2..1..1....2..1..2..2..0..1..2..1 %Y A267975 Cf. A267974. %K A267975 nonn %O A267975 1,1 %A A267975 _R. H. Hardin_, Jan 23 2016