Triangle read by rows: coefficients of rook polynomials.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =4a(5) =2a(6) =1a(7) =9a(8) =18a(9) =6a(10) =1a(11) =16a(12) =72a(13) =96a(14) =24a(15) =1a(16) =20a(17) =130a(18) =320a(19) =265a(20) =44a(21) =1a(22) =24a(23) =204a(24) =752a(25) =1185a(26) =672a(27) =80a(28) =1a(29) =28