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 A283117 #10 Sep 12 2019 19:39:01
%S A283117 2,2,4,8,19,51,169,592,2281,9268,39521,175875,813780,3903533,19367571,
%T A283117 99208196,523695465,2844708347,15877906262,90955375095,534101204061
%N A283117 Number of nonequivalent ways (mod D_3) to place rooks on an n X n X n triangular grid so that no two of them are on the same row, column or diagonal.
%F A283117 a(n) = Sum_{k=0..A004396(n)} A283113(n,k).
%F A283117 a(n) = (A289709(n) + 2*A326611(n) + 3*2^ceiling(n/2))/6. - _Andrew Howroyd_, Sep 12 2019
%Y A283117 Row sums of A283113.
%Y A283117 Cf. A289709, A326611.
%K A283117 nonn,more
%O A283117 1,1
%A A283117 _R. J. Mathar_, Jul 07 2017
%E A283117 Name changed by _Andrew Howroyd_, Sep 12 2019