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

1,1

Links

Table of n, a(n) for n=1..21.

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

Crossrefs

Row sums of A283113.

Cf. A289709, A326611.

Sequence in context: A168055 A005702 A095335 * A334325 A100396 A056630

Adjacent sequences: A283114 A283115 A283116 * A283118 A283119 A283120

Keyword

nonn,more

Author

R. J. Mathar, Jul 07 2017

Extensions

Name changed by Andrew Howroyd, Sep 12 2019

Status

approved