Bishops on an n X n board (see Robinson paper for details).

Terms

a(0) =0a(1) =1a(2) =0a(3) =2a(4) =2a(5) =8a(6) =14a(7) =36a(8) =112a(9) =216a(10) =928a(11) =1440a(12) =8616a(13) =11520a(14) =87864a(15) =100800a(16) =997952a(17) =1008000a(18) =12427904a(19) =10886400a(20) =169435936a(21) =130636800a(22) =2501216992a(23) =1676505600a(24) =39837528576a(25) =23471078400a(26) =679494214656a(27) =348713164800