Number of nX3 0..1 arrays with each 1 adjacent to 3 or 5 king-move neighboring 1s.

Terms

a(0) =1a(1) =4a(2) =9a(3) =16a(4) =34a(5) =76a(6) =157a(7) =325a(8) =692a(9) =1459a(10) =3064a(11) =6460a(12) =13602a(13) =28711a(14) =60557a(15) =127434a(16) =269291a(17) =568608a(18) =1197256a(19) =2531332a(20) =5349057a(21) =11272003a(22) =23844290a(23) =50418087a(24) =106327692a(25) =225034106a(26) =476101282a(27) =1004782085a(28) =2127548485a(29) =4503616178