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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. 3
2, 2, 4, 8, 19, 51, 169, 592, 2281, 9268, 39521, 175875, 813780, 3903533, 19367571, 99208196, 523695465, 2844708347, 15877906262, 90955375095, 534101204061 (list; graph; refs; listen; history; text; internal format)
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

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Last modified April 16 09:04 EDT 2021. Contains 343030 sequences. (Running on oeis4.)