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

A180142

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

Terms

    a(0) =1a(1) =4a(2) =14a(3) =54a(4) =204a(5) =774a(6) =2934a(7) =11124a(8) =42174a(9) =159894a(10) =606204a(11) =2298294a(12) =8713494a(13) =33035364a(14) =125246574a(15) =474845814a(16) =1800277164a(17) =6825368934a(18) =25876938294a(19) =98106921684a(20) =371951579934

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