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 A223682 #8 Aug 22 2018 09:18:34 %S A223682 16,256,2032,9822,35509,105995,275775,646407,1395174,2815594,5372794, %T A223682 9777124,17079747,28794301,47049089,74774613,115931628,175785252, %U A223682 261231028,381179194,547003777,773063487,1077301747,1481933555 %N A223682 Number of 4 X n 0..1 arrays with rows and antidiagonals unimodal. %C A223682 Row 4 of A223680. %H A223682 R. H. Hardin, <a href="/A223682/b223682.txt">Table of n, a(n) for n = 1..210</a> %F A223682 Empirical: a(n) = (1/112)*n^8 + (79/1260)*n^7 + (121/120)*n^6 + (71/36)*n^5 + (475/48)*n^4 - (1757/180)*n^3 + (8893/840)*n^2 - (569/84)*n + 9. %F A223682 Conjectures from _Colin Barker_, Aug 22 2018: (Start) %F A223682 G.f.: x*(16 + 112*x + 304*x^2 - 594*x^3 + 775*x^4 - 442*x^5 + 216*x^6 - 36*x^7 + 9*x^8) / (1 - x)^9. %F A223682 a(n) = 9*a(n-1) - 36*a(n-2) + 84*a(n-3) - 126*a(n-4) + 126*a(n-5) - 84*a(n-6) + 36*a(n-7) - 9*a(n-8) + a(n-9) for n>9. %F A223682 (End) %e A223682 Some solutions for n=3: %e A223682 ..1..1..0....0..0..1....1..0..0....0..0..0....0..1..1....1..1..0....0..1..0 %e A223682 ..1..1..0....0..0..0....0..1..0....1..1..0....0..1..0....0..1..0....0..0..1 %e A223682 ..0..1..1....0..0..0....1..0..0....0..1..1....0..0..0....1..1..0....1..1..1 %e A223682 ..0..0..1....0..1..1....0..1..0....1..1..0....0..1..1....1..0..0....0..1..0 %Y A223682 Cf. A223680. %K A223682 nonn %O A223682 1,1 %A A223682 _R. H. Hardin_, Mar 25 2013