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 A218516 #7 Jul 24 2018 09:39:56 %S A218516 4,36,236,1528,9858,63592,410218,2646208,17069998,110114102,710317326, %T A218516 4582071648,29557748082,190669317026,1229957991200,7934137929012, %U A218516 51181052626992,330155610028966,2129747655406998,13738446168804038 %N A218516 Number of n X 2 arrays of the minimum value of corresponding elements and their horizontal or antidiagonal neighbors in a random 0..3 n X 2 array. %C A218516 Column 2 of A218522. %H A218516 R. H. Hardin, <a href="/A218516/b218516.txt">Table of n, a(n) for n = 1..210</a> %F A218516 Empirical: a(n) = 6*a(n-1) + 3*a(n-2) - 4*a(n-4) + a(n-5). %F A218516 Empirical g.f.: 2*x*(2 + 6*x + 4*x^2 + 2*x^3 - x^4) / (1 - 6*x - 3*x^2 + 4*x^4 - x^5). - _Colin Barker_, Jul 24 2018 %e A218516 Some solutions for n=3: %e A218516 ..0..0....1..1....3..1....2..2....2..2....2..2....1..0....0..0....3..2....2..1 %e A218516 ..0..0....3..3....0..0....3..2....2..1....2..1....0..0....2..0....0..0....1..1 %e A218516 ..0..2....0..0....0..3....2..2....0..0....1..1....0..0....0..0....0..1....1..3 %Y A218516 Cf. A218522. %K A218516 nonn %O A218516 1,1 %A A218516 _R. H. Hardin_, Oct 31 2012