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 A202254 #11 Mar 03 2018 05:35:49 %S A202254 7,31,81,171,309,509,779,1133,1579,2131,2797,3591,4521,5601,6839,8249, %T A202254 9839,11623,13609,15811,18237,20901,23811,26981,30419,34139,38149, %U A202254 42463,47089,52041,57327,62961,68951,75311,82049,89179,96709,104653,113019 %N A202254 Number of zero-sum -n..n arrays of 4 elements with adjacent element differences also in -n..n. %C A202254 Row 4 of A202252. %H A202254 R. H. Hardin, <a href="/A202254/b202254.txt">Table of n, a(n) for n = 1..210</a> %F A202254 Empirical: a(n) = 3*a(n-1) - 2*a(n-2) - 2*a(n-3) + 3*a(n-4) - a(n-5). %F A202254 Conjectures from _Colin Barker_, Mar 03 2018: (Start) %F A202254 G.f.: x*(7 + 10*x + 2*x^2 + 4*x^3 - x^4) / ((1 - x)^4*(1 + x)). %F A202254 a(n) = (22*n^3 + 33*n^2 + 26*n + 12) / 12 for n even. %F A202254 a(n) = (22*n^3 + 33*n^2 + 26*n + 3) / 12 for n odd. %F A202254 (End) %e A202254 Some solutions for n=10: %e A202254 1 -1 1 -7 -7 -5 5 0 2 -6 4 -2 -2 9 -3 -9 %e A202254 5 -8 7 1 1 -3 1 -5 -1 -2 6 3 1 1 1 1 %e A202254 -1 1 1 6 5 1 -4 1 -2 8 0 4 -4 0 6 0 %e A202254 -5 8 -9 0 1 7 -2 4 1 0 -10 -5 5 -10 -4 8 %Y A202254 Cf. A202252. %K A202254 nonn %O A202254 1,1 %A A202254 _R. H. Hardin_, Dec 14 2011