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

Terms

a(0) =1a(1) =3a(2) =6a(3) =14a(4) =30a(5) =66a(6) =142a(7) =306a(8) =654a(9) =1394a(10) =2958a(11) =6258a(12) =13198a(13) =27762a(14) =58254a(15) =121970a(16) =254862a(17) =531570a(18) =1106830a(19) =2301042a(20) =4776846a(21) =9903218a(22) =20505486a(23) =42409074a(24) =87614350a(25) =180821106a(26) =372827022a(27) =768023666a(28) =1580786574a(29) =3251051634