Eight rooks and one berserker on a 3 X 3 chessboard. G.f.: (1 + x^2)/(1 - 4*x + x^2 + 2*x^3).

A180143

Eight rooks and one berserker on a 3 X 3 chessboard. G.f.: (1 + x^2)/(1 - 4*x + x^2 + 2*x^3).

Terms

    a(0) =1a(1) =4a(2) =16a(3) =58a(4) =208a(5) =742a(6) =2644a(7) =9418a(8) =33544a(9) =119470a(10) =425500a(11) =1515442a(12) =5397328a(13) =19222870a(14) =68463268a(15) =243835546a(16) =868433176a(17) =3092970622a(18) =11015778220a(19) =39233275906a(20) =139731384160a(21) =497660704294

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