Number of 2Xn 0..1 arrays with every element equal to 0, 1 or 3 horizontally or antidiagonally adjacent elements, with upper left element zero.

A301885

Number of 2Xn 0..1 arrays with every element equal to 0, 1 or 3 horizontally or antidiagonally adjacent elements, with upper left element zero.

Terms

    a(0) =2a(1) =5a(2) =10a(3) =18a(4) =35a(5) =74a(6) =154a(7) =317a(8) =658a(9) =1370a(10) =2851a(11) =5930a(12) =12338a(13) =25677a(14) =53434a(15) =111194a(16) =231395a(17) =481538a(18) =1002090a(19) =2085365a(20) =4339682a(21) =9030962a(22) =18793603a(23) =39109842a(24) =81388322a(25) =169370645a(26) =352463530a(27) =733483298a(28) =1526392675a(29) =3176452154

External references