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 A321419 #7 Nov 11 2018 00:43:42 %S A321419 1,0,15,10,120,156,760,1350,4350,8770,22896,47610,110110,226260, %T A321419 483180,964696 %N A321419 Number of n element multisets of the 30th roots of unity with zero sum. %C A321419 Equivalently, the number of closed convex paths of length n whose steps are the 30th roots of unity up to translation. For even n, there will be 15 paths of zero area consisting of n/2 steps in one direction followed by n/2 steps in the opposite direction. %Y A321419 Column k=15 of A321414. %Y A321419 Cf. A321418. %K A321419 nonn,more %O A321419 0,3 %A A321419 _Andrew Howroyd_, Nov 09 2018