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 A209035 #8 Mar 18 2018 17:29:28 %S A209035 6,86,576,2517,8235,22249,52208,110285,214440,390344,672932,1108883, %T A209035 1758433,2698447,4024458,5854361,8330650,11624758,15939472,21513945, %U A209035 28626249,37599103,48802532,62660333,79652814,100324030,125284570 %N A209035 Number of 7-bead necklaces labeled with numbers -n..n allowing reversal, with sum zero and first differences in -n..n. %C A209035 Row 7 of A209032. %H A209035 R. H. Hardin, <a href="/A209035/b209035.txt">Table of n, a(n) for n = 1..144</a> %F A209035 Empirical: a(n) = a(n-1) + a(n-2) - a(n-5) - a(n-7) - a(n-8) + a(n-10) + a(n-11) + 2*a(n-12) - 2*a(n-16) - a(n-17) - a(n-18) + a(n-20) + a(n-21) + a(n-23) - a(n-26) - a(n-27) + a(n-28). %e A209035 Some solutions for n=6: %e A209035 -5 -4 -5 -4 -2 -4 -3 -3 -5 -4 -3 -3 -3 -2 -6 -3 %e A209035 -2 -3 -4 -1 0 1 -1 -2 0 -2 2 1 2 -1 -5 -2 %e A209035 0 3 -1 0 1 -1 1 1 -2 -3 -1 1 -2 1 -1 3 %e A209035 1 3 2 5 -2 2 1 2 3 0 -1 -2 3 -2 1 1 %e A209035 4 0 4 1 1 1 2 1 0 5 -2 -2 -1 -1 5 -1 %e A209035 4 2 3 -2 1 -1 1 3 3 4 3 3 -2 5 6 0 %e A209035 -2 -1 1 1 1 2 -1 -2 1 0 2 2 3 0 0 2 %K A209035 nonn %O A209035 1,1 %A A209035 _R. H. Hardin_, Mar 04 2012