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.

2, 2, 4, 8, 19, 51, 169, 592, 2281, 9268, 39521, 175875, 813780, 3903533, 19367571, 99208196, 523695465, 2844708347, 15877906262, 90955375095, 534101204061

Offset: 1

Author

R. J. Mathar, Jul 07 2017

Keywords

• nonn
• more

Crossrefs

Row sums of A283113.

Cf. A289709, A326611.

Formula

a(n) = Sum_{k=0..A004396(n)} A283113(n,k).

a(n) = (A289709(n) + 2*A326611(n) + 3*2^ceiling(n/2))/6. - Andrew Howroyd, Sep 12 2019

Extensions

Name changed by Andrew Howroyd, Sep 12 2019