Number of n X 3 0..1 arrays with every nonzero element less than or equal to at least two horizontal and vertical neighbors.

A202974

Number of n X 3 0..1 arrays with every nonzero element less than or equal to at least two horizontal and vertical neighbors.

Terms

    a(0) =1a(1) =4a(2) =17a(3) =58a(4) =215a(5) =866a(6) =3507a(7) =14120a(8) =56921a(9) =229860a(10) =928443a(11) =3749720a(12) =15144167a(13) =61165438a(14) =247041429a(15) =997775144a(16) =4029911351a(17) =16276407572a(18) =65738788527a(19) =265512410122

External references