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 A350191 #9 Dec 20 2021 01:40:57 %S A350191 1,1,1,1,5,3,1,45,29,5,807,422,29,20022,8270,224,642162,211848,3012 %N A350191 Number of ways of placing maximum number of nonattacking rooks on a triangular board with edge-length n (not counting rotations and reflections as distinct). %C A350191 a(n) = A350041(n) for n <> 10,13,16,19,... %C A350191 Conjecture: a(3*n-2) = A309260(n). There is a nice analogy with A289893(3*n+1) = A002047(n). %H A350191 Alain Brobecker, <a href="http://abrobecker.free.fr/text/NonAttackingRooks.pdf">Non Attacking Rooks on Hexhex and Triangular boards</a> %H A350191 Vaclav Kotesovec, Example: <a href="/A350191/a350191.pdf">All non-identical positions for n = 10</a>, a(10) = 5 %Y A350191 Cf. A350041, A289893. %K A350191 nonn,more,hard %O A350191 1,5 %A A350191 _Vaclav Kotesovec_, Dec 19 2021