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 A215191 #10 Jul 22 2018 12:32:12 %S A215191 0,18,88,276,664,1366,2512,4264,6800,10330,15080,21308,29288,39326, %T A215191 51744,66896,85152,106914,132600,162660,197560,237798,283888,336376, %U A215191 395824,462826,537992,621964,715400,818990,933440,1059488,1197888,1349426 %N A215191 Number of arrays of 4 0..n integers with no sum of consecutive elements equal to a disjoint adjacent sum of an equal number of elements. %C A215191 Row 4 of A215190. %H A215191 R. H. Hardin, <a href="/A215191/b215191.txt">Table of n, a(n) for n = 1..210</a> %F A215191 Empirical: a(n) = 4*a(n-1) - 5*a(n-2) + 5*a(n-4) - 4*a(n-5) + a(n-6). %F A215191 Conjectures from _Colin Barker_, Jul 22 2018: (Start) %F A215191 G.f.: 2*x^2*(9 + 8*x + 7*x^2) / ((1 - x)^5*(1 + x)). %F A215191 a(n) = n*(3*n^3 + n^2 - 1)/3 for n even. %F A215191 a(n) = (3*n^4 + n^3 - n - 3)/3 for n odd. %F A215191 (End) %e A215191 Some solutions for n=6: %e A215191 2 4 6 0 0 6 6 2 0 0 1 6 5 4 3 3 %e A215191 4 3 0 4 5 0 1 3 2 4 4 0 6 5 4 5 %e A215191 1 5 4 0 1 6 2 5 5 1 3 4 2 6 0 3 %e A215191 0 1 6 3 3 3 3 1 4 5 0 3 0 0 3 4 %Y A215191 Cf. A215190. %K A215191 nonn %O A215191 1,2 %A A215191 _R. H. Hardin_, Aug 05 2012