Eight bishops and one elephant on a 3 X 3 chessboard. G.f.: (1+x-5*x^2)/(1-3*x-x^2+6*x^3).

Terms

a(0) =1a(1) =4a(2) =8a(3) =22a(4) =50a(5) =124a(6) =290a(7) =694a(8) =1628a(9) =3838a(10) =8978a(11) =21004a(12) =48962a(13) =114022a(14) =265004a(15) =615262a(16) =1426658a(17) =3305212a(18) =7650722a(19) =17697430a(20) =40911740a(21) =94528318a(22) =218312114a(23) =503994220a(24) =1163124866a(25) =2683496134a(26) =6189647948a(27) =14273690782