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 A208823 #6 Mar 12 2017 23:18:41 %S A208823 1,7,25,210,1755,17339,177097,1888153,20587627,228891069,2582512649, %T A208823 29499246456 %N A208823 Number of n-bead necklaces labeled with numbers -6..6 allowing reversal, with sum zero. %C A208823 Column 6 of A208825. %e A208823 Some solutions for n=3: %e A208823 .-4...-5...-4...-6...-5...-2...-1...-3...-6...-1...-3...-6...-4...-2...-6...-4 %e A208823 .-2....1....0....3...-1...-1....0...-1....1...-1....1....0...-1...-2....2....2 %e A208823 ..6....4....4....3....6....3....1....4....5....2....2....6....5....4....4....2 %K A208823 nonn %O A208823 1,2 %A A208823 _R. H. Hardin_, Mar 01 2012