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 A208827 #13 Jul 07 2018 06:15:43 %S A208827 18,167,828,2821,7582,17339,35288,65769,114442,188463,296660,449709, %T A208827 660310,943363,1316144,1798481,2412930,3184951,4143084,5319125, %U A208827 6748302,8469451,10525192,12962105,15830906,19186623,23088772,27601533,32793926 %N A208827 Number of 6-bead necklaces labeled with numbers -n..n allowing reversal, with sum zero. %C A208827 Row 6 of A208825. %H A208827 R. H. Hardin, <a href="/A208827/b208827.txt">Table of n, a(n) for n = 1..210</a> %F A208827 Empirical: a(n) = (22/15)*n^5 + (11/3)*n^4 + (14/3)*n^3 + (13/3)*n^2 + (43/15)*n + 1. %F A208827 Conjectures from _Colin Barker_, Jul 07 2018: (Start) %F A208827 G.f.: x*(18 + 59*x + 96*x^2 - 2*x^3 + 6*x^4 - x^5) / (1 - x)^6. %F A208827 a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>6. %F A208827 (End) %e A208827 Some solutions for n=3: %e A208827 -3 -3 -3 -2 -2 -3 -3 -2 -3 -3 -3 -3 -2 -3 -3 -2 %e A208827 -1 0 -2 0 -1 -2 -1 -1 0 -3 -1 -1 -1 2 -2 0 %e A208827 3 1 0 0 3 2 0 1 -2 1 0 2 -2 -2 3 1 %e A208827 -2 -1 3 0 0 3 2 -2 -1 3 0 -1 2 -2 2 -2 %e A208827 3 0 3 0 0 -3 -1 2 3 0 3 3 0 2 -1 0 %e A208827 0 3 -1 2 0 3 3 2 3 2 1 0 3 3 1 3 %Y A208827 Cf. A208825. %K A208827 nonn %O A208827 1,1 %A A208827 _R. H. Hardin_, Mar 01 2012