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 A208599 #12 Mar 18 2018 15:43:39 %S A208599 11,77,291,791,1761,3431,6077,10021,15631,23321,33551,46827,63701, %T A208599 84771,110681,142121,179827,224581,277211,338591,409641,491327,584661, %U A208599 690701,810551,945361,1096327,1264691,1451741,1658811,1887281,2138577,2414171 %N A208599 Number of 5-bead necklaces labeled with numbers -n..n not allowing reversal, with sum zero. %C A208599 Row 5 of A208597. %H A208599 R. H. Hardin, <a href="/A208599/b208599.txt">Table of n, a(n) for n = 1..210</a> %F A208599 Empirical: a(n) = (23/12)*n^4 + (23/6)*n^3 + (37/12)*n^2 + (7/6)*n + 1. %F A208599 Conjectures from _Colin Barker_, Mar 07 2018: (Start) %F A208599 G.f.: x*(11 + 22*x + 16*x^2 - 4*x^3 + x^4) / (1 - x)^5. %F A208599 a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n>5. %F A208599 (End) %e A208599 Some solutions for n=4: %e A208599 -4 -3 -4 -4 -3 -3 -3 -3 -3 -4 -4 -4 -4 -4 -4 -1 %e A208599 -1 2 3 2 0 2 1 -1 4 2 0 -1 4 0 0 0 %e A208599 4 -2 2 -4 -3 2 2 2 0 0 0 4 -3 2 -1 1 %e A208599 -2 3 0 3 3 -1 -2 0 1 -2 2 1 4 1 2 -1 %e A208599 3 0 -1 3 3 0 2 2 -2 4 2 0 -1 1 3 1 %Y A208599 Cf. A208597. %K A208599 nonn %O A208599 1,1 %A A208599 _R. H. Hardin_, Feb 29 2012