Number of nX2 0..1 arrays with every element unequal to 0, 1, 2 or 3 king-move adjacent elements, with upper left element zero.

A303721

Number of nX2 0..1 arrays with every element unequal to 0, 1, 2 or 3 king-move adjacent elements, with upper left element zero.

Terms

    a(0) =2a(1) =8a(2) =21a(3) =49a(4) =120a(5) =293a(6) =719a(7) =1774a(8) =4389a(9) =10893a(10) =27096a(11) =67529a(12) =168555a(13) =421238a(14) =1053769a(15) =2638209a(16) =6609224a(17) =16565853a(18) =41538871a(19) =104192734a(20) =261416765a(21) =656024133a(22) =1646562744a(23) =4133274369a(24) =10376622259a(25) =26052793638a(26) =65415654721a(27) =164260171289

External references